Stephanie L. Merhar

Pharmacokinetics of levetiracetam in neonates with seizures.

The pharmacokinetics of levetiracetam were determined prospectively in 18 neonates with seizures. Neonates were found to have lower clearance, higher volume of distribution, and a longer half-life as compared with older children and adults. Mild somnolence was the only adverse effect.

Quantitative Magnetic Resonance Imaging of Bronchopulmonary Dysplasia in the Neonatal Intensive Care Unit Environment

RATIONALE Bronchopulmonary dysplasia (BPD) is a prevalent yet poorly characterized pulmonary complication of premature birth; the current definition is based solely on oxygen dependence at 36 weeks postmenstrual age without objective measurements of structural abnormalities across disease severity. OBJECTIVES We hypothesize that magnetic resonance imaging (MRI) can spatially resolve and quantify the structural abnormalities of the neonatal lung parenchyma associated with premature birth. METHODS Using a unique, small-footprint, 1.5-T MRI scanner within our neonatal intensive care unit (NICU), diagnostic-quality MRIs using commercially available sequences (gradient echo and spin echo) were acquired during quiet breathing in six patients with BPD, six premature patients without diagnosed BPD, and six full-term NICU patients (gestational ages, 23-39 wk) at near term-equivalent age, without administration of sedation or intravenous contrast. Images were scored by a radiologist using a modified Ochiai score, and volumes of high- and low-signal intensity lung parenchyma were quantified by segmentation and threshold analysis. MEASUREMENTS AND MAIN RESULTS Signal increases, putatively combinations of fibrosis, edema, and atelectasis, were present in all premature infants. Infants with diagnosed BPD had significantly greater volume of high-signal lung (mean ± SD, 26.1 ± 13.8%) compared with full-term infants (7.3 ± 8.2%; P = 0.020) and premature infants without BPD (8.2 ± 6.4%; P = 0.026). Signal decreases, presumably alveolar simplification, only appeared in the most severe BPD cases, although cystic appearance did increase with severity. CONCLUSIONS Pulmonary MRI reveals quantifiable, significant differences between patients with BPD, premature patients without BPD, and full-term control subjects. These methods could be implemented to individually phenotype disease, which may impact clinical care and predict future outcomes.

MRI in the Neonatal ICU: Initial Experience Using a Small-Footprint 1.5-T System

OBJECTIVE The objective of our study was to develop a small 1.5-T MRI system for neonatal imaging that can be installed in the neonatal ICU (NICU) and to evaluate its performance in 15 neonates. SUBJECTS AND METHODS A 1.5-T MR system designed for orthopedic use was adapted for neonatal imaging. Modifications included raising and leveling the magnet, construction of a patient table, and integration of imaging electronics from a high-performance adult-sized scanner. The system was used to perform MR examinations of the brain, abdomen, and chest in 15 medically stable neonates using standard clinical protocols. The scanning time was limited to 60 minutes. The MR examinations were performed without administering sedation to the patients. ECG, heart rate, oxygen saturation, and temperature were monitored continuously throughout the examination. The images were evaluated by two pediatric radiologists for overall study quality, motion artifact, spatial resolution, signal-to-noise ratio, and contrast. RESULTS All 15 neonates were successfully imaged without sedation. No adverse MRI-related events were noted. In total, 19 brain and seven abdominal examinations were performed. Six chest and two cardiac examinations were also obtained. Gross (versus physiologic) subject motion proved to be the most influential factor in determining overall study and image quality. High-quality diagnostic images were obtained at each anatomic location. CONCLUSION The customized neonatal MRI system provides state-of-the-art MRI capabilities in the NICU.

Grade and laterality of intraventricular haemorrhage to predict 18-22 month neurodevelopmental outcomes in extremely low birthweight infants.

Aim:  To determine whether extremely low‐birthweight (ELBW) infants with bilateral compared to unilateral intraventricular haemorrhage (IVH) have worse neurodevelopmental outcomes at 18–22 months.

Retrospective respiratory self-gating and removal of bulk motion in pulmonary UTE MRI of neonates and adults.

To implement pulmonary three‐dimensional (3D) radial ultrashort echo‐time (UTE) MRI in non‐sedated, free‐breathing neonates and adults with retrospective motion tracking of respiratory and intermittent bulk motion, to obtain diagnostic‐quality, respiratory‐gated images.

Pulmonary MRI of neonates in the intensive care unit using 3D ultrashort echo time and a small footprint MRI system.

To determine the feasibility of pulmonary magnetic resonance imaging (MRI) of neonatal lung structures enabled by combining two novel technologies: first, a 3D radial ultrashort echo time (UTE) pulse sequence capable of high spatial resolution full‐chest imaging in nonsedated quiet‐breathing neonates; and second, a unique, small‐footprint 1.5T MRI scanner design adapted for neonatal imaging and installed within the neonatal intensive care unit (NICU).

Brain Magnetic Resonance Imaging in Infants with Surgical Necrotizing Enterocolitis or Spontaneous Intestinal Perforation versus Medical Necrotizing Enterocolitis

Magnetic resonance imaging of the brain was performed in 26 preterm infants with necrotizing enterocolitis (NEC) or spontaneous intestinal perforation at term equivalent age. Infants with surgical NEC or spontaneous intestinal perforation had significantly more brain injury on magnetic resonance imaging compared with infants with medical NEC, even after adjustment for confounders.

Fetal and postnatal brain MRI in premature infants with twin–twin transfusion syndrome

Objective:To describe the findings on fetal and postnatal magnetic resonance imaging (MRI) in premature infants with twin–twin transfusion syndrome (TTTS) and to determine whether currently used staging systems and other fetal and postnatal factors correlate with brain injury in this population.Study Design:We performed a prospective study of 22 premature infants with TTTS whose mothers had fetal MRIs. Postnatal brain MRI was performed at term equivalent age (38 to 44 weeks) and medical records were reviewed. Brain injury was scored on fetal and postnatal MRIs using an injury scale incorporating hemorrhagic and nonhemorrhagic injury.Result:The median (range) gestational age (GA) was 31 weeks (26 to 35) and birth weight (BW) was 1296 g (762 to 2330). In all, 5/22 patients (23%) had brain injury seen on fetal MRI and 15/22 patients (68%) had brain injury seen on postnatal MRI. Quintero stage was the only predictor variable that was significantly correlated with the total brain injury score (P=0.05).Conclusion:Postnatal brain injury in premature infants with TTTS is correlated with Quintero stage. GA and BW are not predictive of brain injury in this cohort of infants.

Quantification of neonatal lung parenchymal density via ultrashort echo time MRI with comparison to CT

To demonstrate that ultrashort echo time (UTE) magnetic resonance imaging (MRI) can achieve computed tomography (CT)‐like quantification of lung parenchyma in free‐breathing, non‐sedated neonates. Because infant CTs are used sparingly, parenchymal disease evaluation via UTE MRI has potential for translational impact.

A retrospective review of cyproheptadine for feeding intolerance in children less than three years of age: effects and side effects

Premature infants and those with brain injury often suffer from feeding intolerance and vomiting in the first several years of life. Cyproheptadine is a medication with antihistaminergic, antiserotonergic and anticholinergic effects, thought to increase gastric accommodation. We aimed to retrospectively review our experience using cyproheptadine for feeding intolerance and/or vomiting in children under the age of three.