Sandra Horsch

Resting-state networks in the infant brain

In the absence of any overt task performance, it has been shown that spontaneous, intrinsic brain activity is expressed as systemwide, resting-state networks in the adult brain. However, the route to adult patterns of resting-state activity through neuronal development in the human brain is currently unknown. Therefore, we used functional MRI to map patterns of resting-state activity in infants during sleep. We found five unique resting-states networks in the infant brain that encompassed the primary visual cortex, bilateral sensorimotor areas, bilateral auditory cortex, a network including the precuneus area, lateral parietal cortex, and the cerebellum as well as an anterior network that incorporated the medial and dorsolateral prefrontal cortex. These results suggest that resting-state networks driven by spontaneous signal fluctuations are present already in the infant brain. The potential link between the emergence of behavior and patterns of resting-state activity in the infant brain is discussed.

Neonatal magnetic resonance imaging and outcome at age 30 months in extremely preterm infants

OBJECTIVE To examine associations between brain white matter abnormalities, including diffuse excessive high signal intensities, detected on neonatal magnetic resonance imaging (MRI) with neurodevelopmental outcome at age 30 months. STUDY DESIGN This was a prospective, population-based study of infants born at <27 weeks gestation (n=117) undergoing conventional MRI at term equivalent age (n=107). At age 30 months corrected, 91 of the preterm infants (78%) and 85 term-born controls were assessed with the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III). RESULTS Cerebral palsy (CP) was present in 7% of the preterm group. On the BSID-III, mean composite scores were 96±9.5 for the cognitive scale, 97±14 for language scales, and 103±15 for motor scales, all within the normal range for age. Compared with the term-born controls, however, the preterm infants did not perform as well on all 3 scales, also when MRI was normal. Significant associations were seen between moderate to severe white matter abnormalities and CP (P<.001). The presence of diffuse excessive high signal intensities was not associated with performance on the BSID-III or with CP. CONCLUSION This 3-year cohort of extremely preterm infants had low rates of major brain injury and impaired outcome. Neonatal MRI provides useful information, but this information needs to be treated with caution when predicting outcome.

White matter changes in extremely preterm infants, a population-based diffusion tensor imaging study

Aim:  To investigate cerebral white matter (WM) abnormalities (J Pediatr 2003; 143: 171) and diffuse and excessive high signal intensities (DEHSI), (J Pediatr 1999; 135: 351) in a cohort of extremely preterm infants born in Stockholm during a 3‐year period, using magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI).

Brain abnormalities in extremely low gestational age infants: a Swedish population based MRI study

Aims: Brain abnormalities are common in preterm infants and can be reliably detected by magnetic resonance (MR) imaging at term equivalent age. The aim of the present study was to acquire population based data on brain abnormalities in extremely low gestational age (ELGA) infants from the Stockholm region and to correlate the MR findings to perinatal data, in order to identify risk factors.

Cranial ultrasound and MRI at term age in extremely preterm infants

Objectives Conventional MRI at term age has been reported to be superior to cranial ultrasound (cUS) in detecting white matter (WM) abnormalities and predicting outcome in preterm infants. However, in a previous study cUS was performed during the first 6 weeks only and not in parallel to MRI at term age. Therefore, the aim of the present work was to study brain injuries in preterm infants performing concomitant cUS and MRI at full-term age. Methods In a population-based cohort of 72 extremely low gestational age infants paired cUS and conventional MRI were performed at term age. Abnormalities on MRI were graded according to a previously published scoring system. On cUS images the lateral ventricles, the corpus callosum, the interhemispheric fissure and the subarachnoidal spaces were measured and the presence of cysts, grey matter abnormalities and gyral folding were scored. Results Moderate or severe WM abnormalities were detected on MRI in 17% of infants and abnormalities of the grey matter in 11% of infants. Among infants with normal ultrasound (n=28, 39%) none had moderate or severe WM abnormalities or abnormal grey matter on MRI. All infants with severe abnormalities (n=3, 4%) were identified as severe on MRI and cUS. Conclusions All severe WM abnormalities identified on MRI at term age were also detected by cUS at term, providing the examinations were performed on the same day. Infants with normal cUS at term age were found to have a normal MRI or only mild WM abnormalities on MRI at term age.

Single‐centre vs. population‐based outcome data of extremely preterm infants at the limits of viability

Aim:  In response to the disappointing outcome data of the population‐based EPICure study published in 2000, we compared the outcome of infants 22 0/7 to 25 6/7 weeks of gestational age (GA) in a single tertiary care centre 2000–2004 with that of EPICure.

Ultrasound diagnosis of brain atrophy is related to neurodevelopmental outcome in preterm infants

BACKGROUND Intraventricular haemorrhage and periventricular leukomalacia are associated with poor outcome of very preterm infants, while the role of more subtle cerebral alterations, as detected by cranial ultrasound, is less clear. AIM In this study, we related periventricular echodensities and signs of brain atrophy to neurodevelopmental outcome at 3 y of age. PATIENTS AND METHODS All preterm infants born in 1997 in our institution with a gestational age <32 wk or birthweight <1500 g were subjected to repeated standardized cranial ultrasound examinations until discharge. Survivors were examined at 3 y of age employing the Bayley Scales of Infant Development II. RESULTS Eighty-seven infants were enrolled (birthweight 430-2500 g (median 1200 g), gestational age 24-34 wk (median 29 wk)). Periventricular echodensities were detected in 42 infants (48%); in 12 cases persisting <7 d, in 30 cases >7 d. At discharge, 18 infants (22%) had signs of brain atrophy. Neurodevelopmental outcome was assessed in 64 infants. Infants with signs of brain atrophy scored significantly lower on MDI (atrophy 91.8, no atrophy 101.9; p=0.02), PDI (atrophy 91.4, no atrophy 106.5; p=0.001) and Behaviour Rating Scale (atrophy 41.1, no atrophy 66.4; p=0.01) than infants without atrophy. Periventricular echodensities were not related to outcome. CONCLUSION Our data show that infants with sonographic signs of brain atrophy at discharge achieve lower scores in neurodevelopmental testing at 3 y.

Umbilical artery catheter blood sampling volume and velocity: Impact on cerebral blood volume and oxygenation in very-low-birthweight infants

AIM Blood sampling from umbilical artery catheters decreases cerebral blood volume and cerebral oxygenation. The aim of this study was to assess the impact of sampling volume and velocity. METHODS Forty-eight infants, median birthweight 965 g (480-1500 g), median gestational age 27 wk (23-34 wk), were studied during routine blood sampling from umbilical artery catheters. The sampling procedure was performed following a strict protocol for draw-up volume (1.6 ml), sampling volume (1.7 ml or 0.2 ml), re-injection volume (1.6 ml) and flushing volume (0.6 ml), time of aspiration (40 s or 80 s), re-injection (30 s) and flushing (6 s). In each infant, sampling volume and aspiration time were subject to sequential variation in a randomized fashion (1.7 ml/40 s, 1.7 ml/80 s, 0.2 ml/30 s). Using near-infrared spectroscopy, changes in concentrations of cerebral oxygenated and deoxygenated haemoglobin were measured, and changes in cerebral blood volume and cerebral oxygenation were calculated. RESULTS During all three sampling procedures, oxygenated haemoglobin decreased significantly from baseline, whereas deoxygenated haemoglobin did not change. Correspondingly, a decrease in cerebral blood volume and cerebral oxygenation occurred. This decrease was not affected significantly by extending the sampling time from 40 s to 80 s, whereas it was blunted by reducing the amount of blood withdrawn. CONCLUSION Blood sampling from umbilical artery catheters induces a decrease in cerebral blood volume and cerebral oxygenation. The magnitude of the decrease depends on the blood volume withdrawn but not on sampling velocity.

Umbilical artery catheter blood sampling decreases cerebral blood volume and oxygenation in very low birthweight infants

The aim of this study was to assess whether blood sampling from umbilical artery catheters reduces cerebral blood volume and cerebral oxygenation in very low birthweight infants. A total of 20 infants, median birthweight 890 g (530‐1500 g), median gestation age 26 +4 wk (range: 22 +5 to 30 +6 wk) were studied from 10min before until 10min after routine blood sampling from umbilical artery catheters placed in the high position. Using near infrared spectroscopy, changes in concentrations of cerebral oxygenated and deoxygenated haemoglobin were measured, and changes in cerebral blood volume and cerebral oxygenation index were calculated. Heart rate, oxygen saturation, transcutaneous PO2 and PCO2 were registered continuously. Mean arterial blood pressure was measured before and after sampling. Oxygenated haemoglobin decreased significantly from baseline during blood sampling, whereas deoxygenated haemoglobin did not change significantly. This resulted in a decrease in cerebral blood volume and cerebral oxygenation index. Heart rate increased slightly, but significantly, from baseline. Oxygen saturation, blood pressure, transcutaneous PO2 and PCO2 did not change significantly.

The acoustic hood: a patient-independent device improving acoustic noise protection during neonatal magnetic resonance imaging.

Background:  Magnetic resonance imaging (MRI) is today the imaging modality of choice to investigate the neonatal brain. However, the acoustic noise during scanning is very loud, often exceeding 100 dBA.