Objective Small head circumferences and white matter injury in the form of periventricular leukomalacia have been observed in populations of infants with severe forms of congenital heart defects. This study tests the hypothesis that congenital heart defects delay in utero structural brain development. Methods Full-term infants with hypoplastic left heart syndrome or transposition of the great arteries were prospectively evaluated with preoperative brain magnetic resonance imaging. Patients with independent risk factors for abnormal brain development (shock, end-organ injury, or intrauterine growth retardation) were excluded. Outcome measures included head circumferences and the total maturation score on magnetic resonance imaging. Total maturation score is a previously validated semiquantitative anatomic scoring system used to assess whole brain maturity. The total maturation score evaluates 4 parameters of maturity: (1) myelination, (2) cortical infolding, (3) involution of glial cell migration bands, and (4) presence of germinal matrix tissue. Results The study cohort included 29 neonates with hypoplastic left heart syndrome and 13 neonates with transposition of the great arteries at a mean gestational age of 38.9 ± 1.1 weeks. Mean head circumference was 1 standard deviation below normal. The mean total maturation score for the cohort was 10.15 ± 0.94, significantly lower than reported normative data in infants without congenital heart defects, corresponding to a delay of 1 month in structural brain development. Conclusion Before surgery, term infants with hypoplastic left heart syndrome and transposition of the great arteries have brains that are smaller and structurally less mature than expected. This delay in brain development may foster susceptibility to periventricular leukomalacia in the preoperative, intraoperative, and postoperative periods.

Significant improvements have been achieved in cardiac arrest resuscitation and postarrest resuscitation care, but mortality remains high. Most of the poor outcomes and deaths of cardiac arrest survivors have been attributed to widespread brain injury. This brain injury, commonly manifested as a comatose state, is a marker of poor outcome and a major basis for unfavorable neurological prognostication. Accurate prognostication is important to avoid pursuing futile treatments when poor outcome is inevitable but also to avoid an inappropriate withdrawal of life-sustaining treatment in patients who may otherwise have a chance of achieving meaningful neurological recovery. Inaccurate neurological prognostication leading to withdrawal of life-sustaining treatment and deaths may significantly bias clinical studies, leading to failure in detecting the true study outcomes. The American Heart Association Emergency Cardiovascular Care Science Subcommittee organized a writing group composed of adult and pediatric experts from neurology, cardiology, emergency medicine, intensive care medicine, and nursing to review existing neurological prognostication studies, the practice of neurological prognostication, and withdrawal of life-sustaining treatment. The writing group determined that the overall quality of existing neurological prognostication studies is low. As a consequence, the degree of confidence in the predictors and the subsequent outcomes is also low. Therefore, the writing group suggests that neurological prognostication parameters need to be approached as index tests based on relevant neurological functions that are directly related to the functional outcome and contribute to the quality of life of cardiac arrest survivors. Suggestions to improve the quality of adult and pediatric neurological prognostication studies are provided.

Purpose:To test the feasibility of pediatric perfusion imaging using a pulsed arterial spin labeling (ASL) technique at 1.5 T.Materials and Methods: ASL perfusion imaging was carried out on seven neurologically normal children and five healthy adults. The signal-to-noise ratio (SNR) of the perfusion images along with T1, M 0 , arterial transit time, and the temporal fluctuation of the ASL image series were measured and compared between the two age groups. In addition, ASL perfusion magnetic resonance (MR) was performed on three children with neurologic disorder. Results:In the cohort of neurologically normal children, a 70% increase in the SNR of the ASL perfusion images and a 30% increase in the absolute cerebral blood flow compared to the adult data were observed. The measures of ASL SNR, T1, and M 0 were found to decrease linearly with age. Transit time and temporal fluctuation of the ASL perfusion image series were not significantly different between the two age groups. The feasibility of ASL in the diagnosis of pediatric neurologic disease was also illustrated. Conclusion:ASL is a promising tool for pediatric perfusion imaging given the unique and reciprocal benefits in terms of safety and image quality .

Background-Preoperative brain injury is an increasingly recognized phenomenon in neonates with complex congenital heart disease. Recently, reports have been published that associate preoperative brain injury in neonates with transposition of the great arteries with the performance of balloon atrial septostomy (BAS), a procedure that improves systemic oxygenation preoperatively. It is unclear whether BAS is the cause of brain injury or is a confounder, because neonates who require BAS are typically more hypoxemic. We sought to determine the relationship between preoperative brain injury in neonates with transposition of the great arteries and the performance of BAS. We hypothesized that brain injury results from hypoxic injury, not from the BAS itself. Methods and Results-Infants with transposition of the great arteries (nϭ26) were retrospectively included from a larger cohort of infants with congenital heart disease who underwent preoperative brain MRI as part of 2 separate prospective studies. Data collected included all preoperative pulse oximetry recordings, all values from preoperative arterial blood gas measurements, and BAS procedure data. MRI scans were performed on the day of surgery, before the surgical repair.Of the 26 neonates, 14 underwent BAS. No stroke was seen in the entire cohort, whereas 10 (38%) of 26 patients were found to have hypoxic brain injury in the form of periventricular leukomalacia. Periventricular leukomalacia was not associated with BAS; however, neonates with periventricular leukomalacia had lower preoperative oxygenation (Pϭ0.026) and a longer time to surgery (Pϭ0.028) than those without periventricular leukomalacia. Conclusions-Preoperative brain injury in neonates with transposition of the great arteries is associated with hypoxemia and longer time to surgery. We found no association between BAS and brain injury.

Neonatal congenital heart disease (CHD) is associated with altered cerebral hemodynamics and increased risk of brain injury. Two novel noninvasive techniques, magnetic resonance imaging (MRI) and diffuse optical and correlation spectroscopies (diffuse optical spectroscopy (DOS), diffuse correlation spectroscopy (DCS)), were employed to quantify cerebral blood flow (CBF) and oxygen metabolism (CMRO 2 ) of 32 anesthetized CHD neonates at rest and during hypercapnia. Cerebral venous oxygen saturation (S v O 2 ) and CBF were measured simultaneously with MRI in the superior sagittal sinus, yielding global oxygen extraction fraction (OEF) and global CMRO 2 in physiologic units. In addition, microvascular tissue oxygenation (StO 2 ) and indices of microvascular CBF (BFI) and CMRO 2 (CMRO 2i ) in the frontal cortex were determined by DOS/DCS. Median resting-state MRI-measured OEF, CBF, and CMRO 2 were 0.38, 9.7 mL/minute per 100 g and 0.52 mL O 2 /minute per 100 g, respectively. These CBF and CMRO 2 values are lower than literature reports for healthy term neonates (which are sparse and quantified using different methods) and resemble values reported for premature infants. Keywords: cerebral blood flow; cerebral hemodynamics; diffuse optics; MRI; near-infrared spectroscopy; neonatal ischemia INTRODUCTION Congenital heart disease (CHD) affects B35,000 neonates each year in the United States. These patients suffer both short-and long-term neurologic sequelae. Periventricular leukomalacia is the most common cerebral injury found in this population. This type of injury is characterized by focal necrosis in the periventricular white matter, and it is associated with pyknotic glial nuclei and reactive gliosis. 1,2 During the early stages of brain development, the oligodendrocyte (brain glial cells) precursors are metabolically very active and highly susceptible to injury from reduced blood flow and oxygen delivery. Hence, hypoxiaischemia has been implicated as a major cause of this injury in CHD neonates.Periventricular leukomalacia leads to impaired myelination and has been linked to worse neurodevelopmental outcomes in premature infants and postulated to cause (at least in part) the impaired cognition and cerebral palsy commonly seen in this cohort of infants with CHD. 3,4 Quantification of the hemodynamic and metabolic state of these neonates via measurements of cerebral blood flow (CBF) and the cerebral metabolic rate of oxygen consumption (CMRO 2 ) should provide valuable information toward understanding the interaction between cardiac pathophysiology and subsequent cerebral health. Potentially, such new knowledge could help predict and prevent adverse outcomes.

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Abstract. We employ a hybrid diffuse correlation spectroscopy ͑DCS͒ and near-infrared spectroscopy ͑NIRS͒ monitor for neonates with congenital heart disease ͑n =33͒. The NIRS-DCS device measured changes during hypercapnia of oxyhemoglobin, deoxyhemoglobin, and total hemoglobin concentrations; cerebral blood flow ͑rCBF DCS ͒; and oxygen metabolism ͑rCMRO 2 ͒. Concurrent measurements with arterial spin-labeled magnetic resonance imaging ͑rCBF ASL-MRI , n =12͒ cross-validate rCBF DCS against rCBF ASL-MRI , showing good agreement ͑R = 0.7, p = 0.01͒. The study demonstrates use of NIRS-DCS on a critically ill neonatal population, and the results indicate that the optical technology is a promising clinical method for monitoring this population.

Four very low birth weight, very premature infants were monitored during a 12° postural elevation using diffuse correlation spectroscopy (DCS) to measure microvascular cerebral blood flow (CBF) and transcranial Doppler ultrasound (TCD) to measure macrovascular blood flow velocity in the middle cerebral artery. DCS data correlated significantly with peak systolic, end diastolic, and mean velocities measured by TCD (pA =0.036, 0.036, 0.047). Moreover, population averaged TCD and DCS data yielded no significant hemodynamic response to this postural change (p>0.05). We thus demonstrate feasibility of DCS in this population, we show correlation between absolute measures of blood flow from DCS and blood flow velocity from TCD, and we do not detect significant changes in CBF associated with a small postural change (12°) in these patients.