Neonatal cranial sonography: A concise review for clinicians

Neurosonography: Shaping the future of neuroprotection strategies in extremely preterm infants

This review aims to explore the current application of Cranial Ultrasound Screening (CUS) in the diagnosis and treatment of brain diseases in extremely preterm infants. It also discusses the potential role of emerging ultrasound-derived technologies such as Super Microvascular Structure Imaging (SMI), Shear Wave Elastography (SWE), Ultrafast Doppler Ultrasound (UfD), and 3D ventricular volume assessment and automated segmentation techniques in clinical practice. A systematic search of medical databases was conducted using the keywords "(preterm OR extremely preterm OR extremely low birth weight) AND (ultrasound OR ultrasound imaging) AND (neurodevelopment OR brain development OR brain diseases OR brain injury OR neuro*)" to identify relevant literature. The titles, abstracts, and full texts of the identified articles were carefully reviewed to determine their relevance to the research topic. CUS offers unique advantages in early screening and monitoring of brain diseases in extremely preterm infants, as it can be performed at the bedside without the need for anesthesia or special monitoring. This technique facilitates early detection and intervention of conditions such as intraventricular hemorrhage, white matter injury, hydrocephalus, and hypoxic-ischemic injury in critically ill preterm infants. Continuous refinement of the screening and follow-up processes provides reliable clinical decision-making support for healthcare professionals and parents. Emerging ultrasound technologies, such as SWE, SMI, and UfD, are being explored to provide more accurate and in-depth understanding of brain diseases in extremely preterm infants. SWE has demonstrated its effectiveness in assessing the elasticity of neonatal brain tissue, aiding in the localization and quantification of potential brain injuries. SMI can successfully identify microvascular structures in the brain, offering a new perspective on neurologic diseases. UfD provides a high-sensitivity and quantitative imaging method for the prevention and treatment of neonatal brain diseases by detecting subtle changes in red blood cell movement and accurately assessing the status and progression of brain diseases. CUS and its emerging technologies have significant applications in the diagnosis and treatment of brain diseases in extremely preterm infants. Future research aims to address current technical challenges, optimize and enhance the clinical decision-making capabilities related to brain development, and improve the prevention and treatment outcomes of brain diseases in extremely preterm infants.

Deep Learning With Physics-Embedded Neural Network for Full Waveform Ultrasonic Brain Imaging

The convenience, safety, and affordability of ultrasound imaging make it a vital non-invasive diagnostic technique for examining soft tissues. However, significant differences in acoustic impedance between the skull and soft tissues hinder the successful application of traditional ultrasound for brain imaging. In this study, we propose a physics-embedded neural network with deep learning based full waveform inversion (PEN-FWI), which can achieve reliable quantitative imaging of brain tissues. The network consists of two fundamental components: forward convolutional neural network (FCNN) and inversion sub-neural network (ISNN). The FCNN explores the nonlinear mapping relationship between the brain model and the wavefield, replacing the tedious wavefield calculation process based on the finite difference method. The ISNN implements the mapping from the wavefield to the model. PEN-FWI includes three iterative steps, each embedding the F CNN into the ISNN, ultimately achieving tomography from wavefield to brain models. Simulation and laboratory tests indicate that PEN-FWI can produce high-quality imaging of the skull and soft tissues, even starting from a homogeneous water model. PEN-FWI can achieve excellent imaging of clot models with constant uniform distribution of velocity, randomly Gaussian distribution of velocity, and irregularly shaped randomly distributed velocity. Robust differentiation can also be achieved for brain slices of various tissues and skulls, resulting in high-quality imaging. The imaging time for a horizontal cross-sectional imag e of the brain is only 1.13 seconds. This algorithm can effectively promote ultrasound-based brain tomography and provide feasible solutions in other fields.

Correlation between Transcranial Ultrasound and CT Head to Detect Clinically Significant Conditions in Post-craniectomy Patients Performed by Emergency Physician: A Pilot Study

Background

The main objective is to detect clinically significant conditions by transcranial ultrasound (TCS) in post-decompressive craniectomy (DC) patients who come to the emergency department.

Materials and methods

This was a cross-sectional observational study. We studied 40 post-DC patients. After primary stabilization, TCS was done. Computer tomography of head was done within 2 hours of performing TCS. The correlation between both modalities were assessed by the measurement of lateral ventricle (LV) (Bland-Altman plot), Midline shift and mass lesion. Additionally, normal cerebral anatomy, 3rd and 4th ventricles and external ventricular drainage (EVD) catheter visualization were also done.

Results

About 14/40 patients came with non-neurosurgical complaints and 26/40 patients came with neurosurgical complaints. Patients with non-neurosurgical complaints (4/14) had mass lesions and 1/14 had MLS. Patients with neurosurgical complaints (11/26) had mass lesions and about 5 patients had MLS. A good correlation was found between TCS and CT of head in measuring LV right (CT head = 17.4 ± 13.8 mm and TCS = 17.1 ± 14.8 mm. The mean difference (95% CI) = [0.28 (-1.9 to 1.33), ICC 0.93 (0.88-0.96)], Left [CT head = 17.8 ± 14.4 mm and TCS = 17.1 ± 14.2 mm, the mean difference (95% CI) 0.63 (-1.8 to 0.61), ICC 0.96 (0.93-0.98)], MLS [CT head = 6.16 ± 3.59 (n = 7) and TCS = 7.883 ± 4.17 (n = 6)] and mass lesions (kappa 0.84 [0.72-0.89] [95% CI] p-value < 0.001). The agreement between both modalities for detecting mass lesions is 93.75%.

Conclusion

Point of care ultrasound (POCUS) is a bedside, easily operable, non-radiation hazard and dynamic imaging tool that can be used for TCS as a supplement to CT head in post-DC patients in emergency as well as in ICU. However, assessment of the ventricular system (pre/post-EVD insertion), monitoring of regression/progression of mass lesion, etc. can be done with TCS. Repeated scans are possible in less time which can decrease the frequency of CT head.

How to cite this article

Chouhan R, Sinha TP, Bhoi S, Kumar A, Agrawal D, Nayer J, et al. Correlation between Transcranial Ultrasound and CT Head to Detect Clinically Significant Conditions in Post-craniectomy Patients Performed by Emergency Physician: A Pilot Study. Indian J Crit Care Med 2024;28(3):299-306.

Dual-Probe Transcranial Full-Waveform Inversion: A Brain Phantom Feasibility Study

OBJECTIVE

Despite being a low-cost, portable and safe medical imaging technique, transcranial ultrasound imaging is not used widely in adults because of the severe degradation and distortion of signals caused by the skull. Full-waveform inversion (FWI) has recently been found to have potential as an effective method for transcranial ultrasound tomography to obtain high-quality, subwavelength-resolution acoustic models of the brain using low-frequency ultrasound data. In this study is the first demonstration of this method in recovering a high-resolution 2-D reconstruction of a brain and skull ultrasound imaging phantom using experimentally acquired data.

METHODS

A 2:5 scale brain phantom encased within a 3-D-printed skull-mimicking layer was created to simulate a clinical transcranial imaging target. To obtain tomographic ultrasound data on the brain and skull phantom, a tomographic ultrasound acquisition system was designed and implemented using commercially available low-frequency cardiac probes. FWI reconstructions of the brain and skull phantom were performed using the acquired tomographic data and were compared with corresponding synthetic reconstructions. This comparison was used to evaluate the feasibility of the proposed imaging system when employing different transducer array configurations.

RESULTS

We demonstrate the successful FWI reconstruction of the brain phantom within the skull mimic from experimentally acquired tomographic ultrasound data. To mitigate the effects of the skull-mimicking material, a reflection-matching algorithm was applied to model the morphology of the skull layer prior to performing the inversion.

CONCLUSION

The findings of this study provide a promising step toward the clinical use of FWI for transcranial ultrasound imaging in adults.

Pediatric ECLS Neurologic Management and Outcomes

Neurologic complications associated with extracorporeal life support (ECLS), including seizures, ischemia/infarction, and intracranial hemorrhage significantly increase morbidity and mortality in pediatric and neonatal patients. Prompt recognition of adverse neurologic events may provide a window to intervene with neuroprotective measures. Many neuromonitoring modalities are available with varying benefits and limitations. Several pre-ECLS and ECLS-related factors have been associated with an increased risk for neurologic complications. These may be patient- or circuit-related and include modifiable and non-modifiable factors. ECLS survivors are at risk for long-term neurological sequelae affecting neurodevelopmental outcomes. Possible long-term outcomes range from normal development to severe impairment. Patients should undergo a neurological evaluation prior to discharge, and neurodevelopmental assessments should be included in each patient's structured, multidisciplinary follow-up. Safe pediatric and neonatal ECLS management requires a thorough understanding of neurological complications, neuromonitoring techniques and limitations, considerations to minimize risk, and an awareness of possible long-term ramifications. With a focus on ECLS for respiratory failure, this manuscript provides a review of these topics and summarizes best practice guidelines from international organizations and expert consensus.

Intracranial Imaging of Preterm Infants with Suspected Hypoxic Ischemic Encephalopathy: Comparing MRI and Ultrasound

AIMS

We correlate ultrasound, MRI, and clinical findings in neonates with suspected hypoxic ischemic injury.

BACKGROUND

Recent advances in neuroimaging have led to improved detection of subtle insults associated with neurodevelopmental outcomes, beyond more historically described lesions such as large hemorrhages and hydrocephalus.

OBJECTIVE

In this study, we compare cranial ultrasound to MRI for the evaluation of suspected HIE in preterm infants.

METHODS

147 premature infant patients with paired ultrasound and MRI exams were retrospectively analyzed to compare imaging finding accuracy and clinical value.

RESULT

We confirm that ultrasound is highly sensitive and specific for hydrocephalus, ventricular prominence, and gross structural abnormalities. Ultrasound is not a substitute for MRI in cases of small hemorrhages or white matter injury, however, certain US findings were associated with Apgar score and MRI sequelae of HIE.

CONCLUSION

Choosing between ultrasound and MRI for preterm neonates at risk for intracranial abnormalities based on their strengths can reduce cost and maximize clinical utility. MRI provides a highly sensitive identification of subtle brain injury, yet ultrasound is correlated with the peripartum clinical picture as measured by Apgar score.

European recommendations on practices in pediatric neuroradiology: consensus document from the European Society of Neuroradiology (ESNR), European Society of Paediatric Radiology (ESPR) and European Union of Medical Specialists Division of Neuroradiology (UEMS)

Pediatric neuroradiology is a subspecialty within radiology, with possible pathways to train within the discipline from neuroradiology or pediatric radiology. Formalized pediatric neuroradiology training programs are not available in most European countries. We aimed to construct a European consensus document providing recommendations for the safe practice of pediatric neuroradiology. We particularly emphasize imaging techniques that should be available, optimal site conditions and facilities, recommended team requirements and specific indications and protocol modifications for each imaging modality employed for pediatric neuroradiology studies. The present document serves as guidance to the optimal setup and organization for carrying out pediatric neuroradiology diagnostic and interventional procedures. Clinical activities should always be carried out in full agreement with national provisions and regulations. Continued education of all parties involved is a requisite for preserving pediatric neuroradiology practice at a high level.

Applications of elastography in operative neurosurgery: A systematic review

Elastography is an imaging technology capable of measuring tissue stiffness and consistency. The technology has achieved widespread use in the workup and management of diseases of the liver, breast, thyroid, and prostate. Although elastography is increasingly being applied in neurosurgery, it has not yet achieved widespread adoption and many clinicians remain unfamiliar with the technology. Therefore, we sought to summarize the range of applications and elastography modalities available for neurosurgery, report its effectiveness in comparison with conventional imaging methods, and offer recommendations. All full-text English-language manuscripts on the use of elastography for neurosurgical procedures were screened using the PubMed/MEDLINE, Embase, Cochrane Library, Scopus, and Web of Science databases. Thirty-two studies were included with 990 patients, including 21 studies on intracranial tumors, 5 on hydrocephalus, 4 on epilepsy, 1 on spinal cord compression, and 1 on adolescent scoliosis. Twenty studies used ultrasound elastography (USE) whereas 12 used magnetic resonance elastography (MRE). MRE studies were mostly used in the preoperative setting for assessment of lesion stiffness, tumor-brain adherence, diagnostic workup, and operative planning. USE studies were performed intraoperatively to guide resection of lesions, determine residual microscopic abnormalities, assess the tumor-brain interface, and study mechanical properties of tumors. Elastography can assist with resection of brain tissue, detection of microscopic lesions, and workup of hydrocephalus, among other applications under investigation. Its sensitivity often exceeds that of conventional MRI and ultrasound for identifying abnormal tissue and lesion margins.

High-resolution neurosonographic examination of the lenticulostriate vessels in neonates with hypoxic-ischemic encephalopathy

OBJECTIVE

To assess the feasibility of visualizing lenticulostriate vessels (LV) using a linear high-resolution ultrasound probe and characterize LV morphology to determine whether morphological alterations in LV are present in neonatal hypoxic-ischemic encephalopathy (HIE) as compared to the unaffected infants.

METHODS

We characterized LV by their echogenicity, width, length, tortuosity, and numbers of visualized stems/branches in neurosonographic examinations of 80 neonates. Our population included 45 unaffected (non-HIE) and 35 with clinical and/or imaging diagnosis of HIE. Of the neonates with clinical diagnosis of HIE, 16 had positive MRI findings for HIE (HIE+MRI) and 19 had negative MRI findings (HIE-MRI). Annotations were performed twice with shuffled data sets at a 1-month interval and intrarater reliability was assessed. Focused comparison was conducted between non-HIE, HIE+MRI and HIE-MRI neonates whose images were acquired with a high frequency linear transducer.

RESULTS

Studies acquired with the two most frequently utilized transducers significantly differed in number of branches (p = 0.002), vessel thickness (p = 0.007) and echogenicity (p = 0.009). Studies acquired with the two transducers also significantly differed in acquisition frequency (p < 0.001), thermal indices (p < 0.001) and use of harmonic imaging (p < 0.001). Groupwise comparison of vessels imaged with the most frequently utilized transducer found significantly fewer branches in HIE + MRI compared to HIE-MRI negative and non-HIE patients (p = 0.005).

CONCLUSION

LV can be visualized in the absence of pathology using modern high-resolution neurosonography. Visualization of LV branches varies between HIE + MRI, HIE-MRI neonates and controls.

ADVANCES IN KNOWLEDGE

High-resolution neurosonography is a feasible technique to assess LV morphology in healthy neonates and neonates with HIE.

Fifteen-minute consultation: Point of care ultrasound in the management of paediatric shock

The use of point of care ultrasound (POCUS) in the assessment of the acutely shocked adult patient has been well established for over a decade. Comparatively, its use in paediatrics has been limited, but this is starting to change with the recent introduction of Children's Acute Ultrasound training. This article highlights the pathophysiology of shock in children and demonstrates how bedside ultrasound can be used to assist decision making in the clinical assessment of the neonate, infant or older child presenting with undifferentiated shock. We discuss a structured protocol to use when performing the POCUS examination and explain how this could lead to a more rapid correlation of the ultrasound findings with the underlying cause of shock.

Superficial anatomy of the neonatal cerebrum - an ultrasonographic roadmap

Neurosonography is an essential imaging modality for assessing the neonatal brain, particularly as a screening tool to evaluate intracranial hemorrhage, hydrocephalus and periventricular leukomalacia. The primary advantages of neurosonography include portability, accessibility and lack of ionizing radiation. Its main limitations are intrinsic operator dependence and the need for an open fontanelle. Neurosonographic imaging acquisition is typically performed by placing a sector transducer over the anterior fontanelle and following sagittal and coronal sweeps. The sensitivity of neurosonography has markedly improved thanks to the adoption of modern imaging equipment, the use of dedicated head probes, and the employment of advanced diagnostic US techniques. These developments have facilitated more descriptive identification of specific cerebral anatomical details, improving understanding of the cerebral anatomy by conventional US. Such knowledge is fundamental for enhanced diagnostic sensitivity and is a key to understanding pathological states. Furthermore, familiarity with normal anatomy is crucial for understanding pathological states. Our primary goal in this review was to supplement these technological developments with a roadmap to the cerebral landscape. We accomplish this by presenting a systematic approach to using routine US for consistent identification of the most crucial cerebral landmarks, reviewing their relationship with adjacent structures, and briefly describing their primary function.

Impact of Erythropoietin in the management of Hypoxic Ischaemic Encephalopathy in resource-constrained settings: protocol for a randomized control trial

Background

Perinatal asphyxia, more appropriately known as hypoxic-ischemic encephalopathy (HIE), is a condition characterized by clinical and laboratory evidence of acute or sub-acute brain injury resulting from systemic hypoxemia and/or reduced cerebral blood flow. HIE is a common and devastating clinical condition in resource-poor countries with poor treatment outcome. This paper describes the protocol for an ongoing study that aims to evaluate the neuroprotective effects of Erythropoietin (EPO) as compared to routine care in the management of moderate to severe HIE among term infants.

Methods

This study is a double-blind randomized controlled trial that will be conducted in the neonatal wards of the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria, over a two-year period after ethical approvals and consents. One hundred and twenty-eight term newborns (≥ 37 weeks gestation) diagnosed with moderate/ severe HIE at admission will be allocated by randomization to receive either EPO or normal saline. All the participants will be offered standard care according to the unit protocol for HIE. Baseline investigations and close monitoring of the babies are done until discharge. Participants are followed up for 2 years to monitor their outcome (death or neurological development) using standard instruments.

Discussion

Previous trials had shown that EPO confers neuroprotective benefits and improve neurological and behavioral outcome in infants with HIE both singly or as an adjuvant to therapeutic hypothermia. This study hypothesized that administering EPO to newborns with moderate /severe HIE can positively influence their clinical and neurological outcomes and will provide evidence to either support or disprove the usefulness of Erythropoietin as a sole agent in the treatment of HIE, especially in resource-limited environment with the highest burden of the disease.

Trial registration

The study has been registered with the Pan African Clinical trials registry on the 2nd of December 2018, with registration number PACTR201812814507775.

Ultrasound-Based Phenotyping of Lateral Ventricles to Predict Hydrocephalus Outcome in Premature Neonates

OBJECTIVE

Prediction of post-hemorrhagic hydrocephalus (PHH) outcome-i.e., whether it requires intervention or not-in premature neonates using cranial ultrasound (CUS) images is challenging. In this paper, we present a novel fully-automatic method to perform phenotyping of the brain lateral ventricles and predict PHH outcome from CUS.

METHODS

Our method consists of two parts: ventricle quantification followed by prediction of PHH outcome. First, cranial bounding box and brain interhemispheric fissure are detected to determine the anatomical position of ventricles and correct the cranium rotation. Then, lateral ventricles are extracted using a new deep learning-based method by incorporating the convolutional neural network into a probabilistic atlas-based weighted loss function and an image-specific adaption. PHH outcome is predicted using a support vector machine classifier trained using ventricular morphological phenotypes and clinical information.

RESULTS

Experiments demonstrated that our method achieves accurate ventricle segmentation results with an average Dice similarity coefficient of 0.86, as well as very good PHH outcome prediction with accuracy of 0.91.

CONCLUSION

Automatic CUS-based ventricular phenotyping in premature newborns could objectively and accurately predict the progression to severe PHH.

SIGNIFICANCE

Early prediction of severe PHH development in premature newborns could potentially advance criteria for diagnosis and offer an opportunity for early interventions to improve outcome.

Cranial Suture Measurement by 2-point Method in Ultrasound Screening of Craniosynostosis

Background:

Diagnostic imaging for craniosynostosis currently relies entirely on radiation images, but it has been estimated that a risk of cancer from diagnostic x-rays may exist. Use of ultrasound imaging has been reported, but very little has been written on normal findings of the cranial suture. Also, ultrasound diagnostic methods have not been established. To obtain images for the diagnosis of abnormal sutures in craniosynostosis, we investigated the normal ultrasonographic appearance of the suture. To establish screening methods for craniosynostosis, we prepared a 2-point method for simple evaluation and confirmed its usefulness.

Methods:

Ultrasonography was performed in infants with normal head, deformational plagiocephaly, and craniosynostosis. We focused on the measurement indices and decided on the order for making our observations. Furthermore, we developed an evaluation method (2-point method) and recorded our finding in a useful table.

Results:

We could clearly judge whether the cranial suture was patent or closed and were able to measure the suture width. Even for 2-year-old children, the width of the sutures at the points measured exceeded the echocardiographic resolution. By using the 2-point evaluation method, all the sutures could be inspected in about 2 minutes. Sensitivity was 100% and specificity was 95.1%.

Conclusions:

Our present studies showed that normal or abnormal suture can be clearly distinguished by ultrasound. By evaluating the fixed points instead of the whole line, it was possible to shorten the inspection time. Ultrasound screening by applying the 2-point method is very useful.

Transcranioplasty Ultrasound Through a Sonolucent Cranial Implant Made of Polymethyl Methacrylate: Phantom Study Comparing Ultrasound, Computed Tomography, and Magnetic Resonance Imaging

BACKGROUND

Current methods of transcranial diagnostic ultrasound imaging are limited by the skull's acoustic properties. Craniotomy, craniectomy, and cranioplasty procedures present opportunities to circumvent these limitations by substituting autologous bone with synthetic cranial implants composed of sonolucent biomaterials.

OBJECTIVE

This study examined the potential to image the brain using transcranioplasty ultrasound (TCU) through a sonolucent cranial implant.

MATERIALS AND METHODS

A validated adult brain phantom was imaged using computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound without an implant. Next, for experimental comparison, TCU was performed through a sonolucent implant composed of clear polymethyl methacrylate.

RESULTS

All imaging modalities successfully revealed elements of the brain phantom, including the bilateral ventricular system, the falx cerebri, and a deep hyperdense mass representing a brain tumor or hematoma. In addition, ultrasound images were captured which closely resembled axial images obtained with both CT and MRI.

CONCLUSION

The results obtained in this first-ever, preclinical, phantom study suggest TCU is now a viable immediate and long-term diagnostic imaging modality deserving of further clinical investigation.

Respiratory Variation of Internal Carotid Artery Blood Flow Peak Velocity Measured by Transfontanelle Ultrasound to Predict Fluid Responsiveness in Infants

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

Cranial sonography is a widely used point-of-care modality in infants. The authors evaluated that the respiratory variation of the internal carotid artery blood flow peak velocity as measured using transfontanelle ultrasound can predict fluid responsiveness in infants.

Methods

This prospective observational study included 30 infants undergoing cardiac surgery. Following closure of the sternum, before and after the administration of 10ml · kg–1 crystalloid, the respiratory variation of the aorta blood flow peak velocity, pulse pressure variation, and central venous pressure were obtained. The respiratory variation of the internal carotid artery blood flow peak velocity was measured using transfontanelle ultrasound. Response to fluid administration was defined as an increase in stroke volume index, as measured with transesophageal echocardiography, greater than 15% of baseline.

Results

Seventeen subjects (57%) were responders to volume expansion. Before fluid loading, the respiratory variation of the internal carotid artery and the aorta blood flow peak velocity (means ± SD) of the responders were 12.6 ± 3.3% and 16.0 ± 3.8%, and those of the nonresponders were 8.2 ± 3.2% and 10.9 ± 3.5%, respectively. Receiver operating characteristic curve analysis showed that the respiratory variation of the internal carotid artery and the aorta blood flow peak velocity could predict fluid responsiveness; the area under the curve was 0.828 (P &lt; 0.0001; 95% CI, 0.647 to 0.940) and 0.86 (P = 0.0001; 95% CI, 0.684 to 0.959), respectively. The cutoff values of the respiratory variation of the internal carotid artery and the aorta blood flow peak velocity were 7.8% (sensitivity, 94%; specificity, 69%) and 13% (sensitivity, 77%; specificity, 92%), respectively.

Conclusions

The respiratory variation of the internal carotid artery blood flow peak velocity as measured using transfontanelle ultrasound predicted an increase in stroke volume in response to fluid. Further research is required to establish any wider generalizability of the results.

Pediatric neuro MRI: tricks to minimize sedation

Magnetic resonance imaging (MRI) is the workhorse modality in pediatric neuroimaging because it provides excellent soft-tissue contrast without ionizing radiation. Until recently, studies were uninterpretable without sedation; however, given development of shorter sequences, sequences that correct for motion, and studies showing the potentially deleterious effects of sedation on immature laboratory animals, it is prudent to minimize sedation when possible. This manuscript provides basic guidelines for performing pediatric neuro MRI without sedation by both modifying technical factors to reduce scan time and noise, and using a multi-disciplinary team to coordinate imaging with the patient's biorhythms.

Editorial brain malformation surveillance in the Zika era

The current surveillance systems for congenital microcephaly are necessary to monitor the impact of Zika virus (ZIKV) on the developing human brain, as well as the ZIKV prevention efforts. However, these congenital microcephaly surveillance systems are insufficient. Abnormalities of neuronal differentiation, development and migration may occur among infants with normal head circumference who have intrauterine exposure to ZIKV. Therefore, surveillance for congenital microcephaly does not ascertain many of the infants seriously impacted by congenital ZIKV infection. Furthermore, many infants with normal head circumference and with malformations of the brain cortex do not have clinical manifestations of their congenital malformations until several months to many years after birth, when they present with clinical manifestations such as seizures/epilepsy, developmental delays with or without developmental regression, and/or motor impairment.

In response to the ZIKV threat, public health surveillance systems must be enhanced to ascertain a wide variety of congenital brain malformations, as well as their clinical manifestations that lead to diagnostic brain imaging. Birth Defects Research (Part A) 106:869–874, 2016. © 2016 The Authors Birth Defects Research Part A: Clinical and Molecular Teratology Published by Wiley Periodicals, Inc.

White matter microstructure of 6-year old children born preterm and full term

AIM

We previously observed a complex pattern of differences in white matter (WM) microstructure between preterm-born (PT) and full-term-born (FT) children and adolescents age 9-17 years. The aim of this study was to determine if the same differences exist as early as age 6 years.

METHOD

We obtained diffusion MRI (dMRI) scans in children born PT at age 6 years (n = 20; 11 males) and FT (n = 38; 14 males), using two scanning protocols: 30 diffusion directions (b = 1000 s/mm²) and 96 diffusion directions (b = 2500 s/mm²). We used deterministic tractography and analyzed fractional anisotropy (FA) along bilateral cerebral WM pathways that demonstrated differences in the older sample.

RESULTS

Compared to the FT group, the PT group showed (1) significantly decreased FA in the uncinate fasciculi and forceps major and (2) significantly increased FA in the right anterior thalamic radiation, inferior fronto-occipital fasciculi, and inferior longitudinal fasciculi. This pattern of group differences resembles findings in the previous study of older PT and FT participants. Group differences were similar across dMRI acquisition protocols.

INTERPRETATION

The underlying neurobiology driving the pattern of PT-FT differences in FA is present as early as age 6 years. Generalization across dMRI acquisition protocols demonstrates the robustness of group differences in FA. Future studies will use quantitative neuroimaging techniques to understand the tissue properties that give rise to this consistent pattern of WM differences after PT birth.

Comparison of preterm and term equivalent age MRI for the evaluation of preterm brain injury

OBJECTIVE

To compare information obtained from preterm magnetic resonance imaging (MRI; 31-34 weeks) brain scan to that done at term equivalent age.

STUDY DESIGN

Prospective observational study of premature infants with evidence or suspicion of parenchymal brain injury on cranial ultrasound. Brain injury on two scans scored using a scoring system and analyzed.

RESULTS

Fourteen infants with a median (range) gestation at birth of 28 (25-29) weeks and birth weight of 1254 (680-1557) grams were studied. There was a strong correlation between the brain injury scores for the two scans (Spearman ρ=0.87, P=0.001) with excellent agreement between two radiologists (interclass correlation coefficient 0.9-0.94). There was also a high level of agreement between the preterm and term MRI two scores (Intraclass correlation coefficient, 0.79 (0.53-0.94)).

CONCLUSIONS

Preterm MRI is a feasible option for the assessment of preterm brain injury and analysis of data obtained from scan at preterm age is comparable to that obtained at term equivalent age.