Ultra-Wideband Radar for Simultaneous and Unobtrusive Monitoring of Respiratory and Heart Rates in Early Childhood: A Deep Transfer Learning Approach.

Unobtrusive monitoring of children's heart rate (HR) and respiratory rate (RR) can be valuable for promoting the early detection of potential health issues, improving communication with healthcare providers and reducing unnecessary hospital visits. A promising solution for wireless vital sign monitoring is radar technology. This paper presents a novel approach for the simultaneous estimation of children's RR and HR utilizing ultra-wideband (UWB) radar using a deep transfer learning algorithm in a cohort of 55 children. The HR and RR are calculated by processing radar signals via spectrogram from time epochs of 10 s (25 sample length of hamming window with 90% overlap) and then transforming the resultant representation into 2-dimensional images. These images were fed into a pre-trained Visual Geometry Group-16 (VGG-16) model (trained on ImageNet dataset), with weights of five added layers fine-tuned using the proposed data. The prediction on the test data achieved a mean absolute error (MAE) of 7.3 beats per minute (BPM < 6.5% of average HR) and 2.63 breaths per minute (BPM < 7% of average RR). We also achieved a significant Pearson's correlation of 77% and 81% between true and extracted for HR and RR, respectively. HR and RR samples are extracted every 10 s.

Accuracy of Detecting Obstructive Sleep Apnea Using Ambulatory Sleep Studies in Patients With Syndromic Craniosynostosis.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is seen in up to two-third of the patients with syndromic craniosynostosis. Gold standard to diagnose OSA is the hospital-based polysomnography, although alternatively ambulatory home sleep apnea devices are available. Aim of this study was to assess (1) accuracy of ambulatory sleep studies, (2) clinical decision making following sleep studies, and (3) course of OSA during long-term follow-up. MATERIALS AND METHODS: A retrospective cohort study was performed in children with syndromic craniosynostosis, of whom polysomnographies and home sleep apnea device recordings were collected. Measurements of apnea-hypopnea index, respiratory event index, total sleep/recording time, heart rate, oxygen saturation, and oxygen desaturation index were derived from the sleep studies. Primary clinical care subsequent to the sleep studies was determined using electronic patient files. RESULTS: In total, 123 patients were included, with 149 polysomnographies and 108 ambulatory studies. Performing an ambulatory study was associated with increased age at time of measurement (OR=1.1, 95% CI=1.02 to 1.17, P =0.01). No significant difference was found between the 2 types of sleep studies regarding sleep study parameters. Subsequent to sleep studies, patients with no-mild OSA had expectant care whereas patients with moderate-severe OSA underwent OSA-related treatment. OSA was most prevalent up to the age of 5 years, but also noticeable after the age of 10 years in patients with the Crouzon syndrome. CONCLUSIONS: Ambulatory sleep studies are reliable for diagnosing OSA in older children and can be used to determine clinical decision-making. Hence, we recommend implementing ambulatory sleep studies in a protocolized management.

Saethre-Chotzen syndrome: long-term outcome of a syndrome-specific management protocol.

AIM: To assess the long-term outcomes of our management protocol for Saethre-Chotzen syndrome, which includes one-stage fronto-orbital advancement. METHOD: All patients born with Saethre-Chotzen syndrome between January 1992 and March 2017 were included. Evaluated parameters included occipital frontal head circumference (OFC), fundoscopy, neuroimaging (ventricular size, tonsillar position, and the presence of collaterals/an abnormal transverse sinus), polysomnography, and ophthalmological outcomes. The relationship between papilledema and its associated risk factors was evaluated with Fisher's exact test. RESULTS: Thirty-two patients (21 females, 11 males) were included. Median (SD) age at first surgery was 9.6 months (3.1mo) for patients who were primarily referred to our center (range: 3.6-13.0mo), the median (SD) age at last follow-up was 13 years (5y 7mo; range: 3-25y). Seven patients had papilledema preoperatively, which recurred in two. Two patients had papilledema solely after first surgery. Second cranial vault expansion was indicated in 20%. Thirteen patients had an OFC deflection, indicating restricted skull growth, one patient had ventriculomegaly, and none developed hydrocephalus. Eleven patients had emissary veins, while the transverse sinus was aberrant unilaterally in 13 (hypoplastic n=10 and absent n=3). Four patients had mild tonsillar descent, one of which was a Chiari type I malformation. Four patients had obstructive sleep apnoea (two mild, one moderate, and one severe). An aberrant transverse sinus was associated with papilledema (p=0.01). INTERPRETATION: Single one-stage fronto-orbital advancement was sufficient to prevent intracranial hypertension for 80% of our patients with Saethre-Chotzen syndrome. Follow-up should focus on OFC deflection and venous anomalies.

Adult Saethre-Chotzen Syndrome: A Unique Abnormal Breathing Pattern.

ABSTRACT: A 35-year-old male with Saethre-Chotzen syndrome presented with severe complaints. Neuroimaging showed a Chiari-I malformation, mild ventriculomegaly, a syrinx of the wide central canal, and various cerebral vascular anomalies including a large occipital emissary vein on the right. Ultrasound of this vein confirmed blocking of the outflow-track when turning his head to the right, which also provoked the headaches and bruit. Polysomnography revealed severe positional sleep apnea with a mixed breathing pattern, the central components consisted of periodic breathing with, at times, crescendo-decrescendo reminiscent of a Cheyne-Stokes versus Biot breathing pattern, pointing to possible brain stem/pontine problems. Continuous positive airway pressure was initiated, and the patient was instructed to avoid sleeping in the right lateral position. One year later, nearly all his complaints have resolved. A questionnaire was sent to all adult Saethre-Chotzen patients in our craniofacial unit, none reported any of the severe symptoms as described by our index case.

Diagnostic and predictive value of Doppler ultrasound for evaluation of the brain circulation in preterm infants: a systematic review.

INTRODUCTION: Very and extremely preterm infants frequently have brain injury-related long-term neurodevelopmental problems. Altered perfusion, for example, seen in the context of a hemodynamically significant patent ductus arteriosus (PDA), has been linked to injury of the immature brain. However, a direct relation with outcome has not been reviewed systematically. METHODS: A systematic review was conducted to provide an overview of the value of different cerebral arterial blood flow parameters assessed by Doppler ultrasound, in relation to brain injury, to predict long-term neurodevelopmental outcome in preterm infants. RESULTS: In total, 23 studies were included. Because of heterogeneity of studies, a meta-analysis of results was not possible. All included studies on resistance index (RI) showed significantly higher values in subjects with a hemodynamically significant PDA. However, absolute differences in RI values were small. Studies using Doppler parameters to predict brain injury and long-term neurodevelopmental outcome were inconsistent. DISCUSSION: There is no clear evidence to support the routine determination of RI or other Doppler parameters in the cerebral arteries to predict brain injury and long-term neurodevelopmental outcome in the preterm infant. However, there is evidence that elevated RI can point to the presence of a hemodynamically significant PDA.

Intracranial hypertension and cortical thickness in syndromic craniosynostosis.

AIM: To evaluate the impact of risk factors for intracranial hypertension (ICH) on cerebral cortex thickness in syndromic craniosynostosis. METHOD: ICH risk factors including papilloedema, hydrocephalus, obstructive sleep apnea (OSA), cerebellar tonsillar position, occipitofrontal circumference (OFC) curve deflection, age, and sex were collected from the records of patients with syndromic craniosynostosis (Apert, Crouzon, Pfeiffer, Muenke, Saethre-Chotzen syndromes) and imaging. Magnetic resonance images were analysed and exported for statistical analysis. A linear mixed model was developed to determine correlations with cerebral cortex thickness changes. RESULTS: In total, 171 scans from 107 patients (83 males, 88 females [including repeated scans], mean age 8y 10mo, range 1y 1mo-34y, SD 5y 9mo) were evaluated. Mean cortical thickness in this cohort was 2.78mm (SD 0.17). Previous findings of papilloedema (p=0.036) and of hydrocephalus (p=0.007) were independently associated with cortical thinning. Cortical thickness did not vary significantly by sex (p=0.534), syndrome (p=0.896), OSA (p=0.464), OFC (p=0.375), or tonsillar position (p=0.682). INTERPRETATION: Detection of papilloedema or hydrocephalus in syndromic craniosynostosis is associated with significant changes in cortical thickness, supporting the need for preventative rather than reactive treatment strategies. WHAT THIS PAPER ADDS: Papilloedema is associated with thinning of the cerebral cortex in syndromic craniosynostosis, independently of hydrocephalus.

Hipertensión intracraneal y grosor cortical en craneosinostosis sindrómica OBJETIVO: Evaluar el impacto de los factores de riesgo de hipertensión intracraneal (HIC) en el grosor de la corteza cerebral en la craneosinostosis sindrómica. MÉTODO: La neuroimagen, y, los factores de riesgo para HIC que incluyeron papiledema, hidrocefalia, apnea obstructiva del sueño (SAOS), posición de la tonsila cerebelosa, edad de desviación de la curva de circunferencia occipitofrontal (CFO) y el sexo, se recogieron de los registros de pacientes con craneosinostosis sindrómica (Apert, Crouzon, Pfeiffer, Muenke, Saethre-Chotzensis). Las imágenes de resonancia magnética fueron analizadas y exportadas para análisis estadístico. Se desarrolló un modelo mixto lineal para determinar las correlaciones con los cambios en el espesor de la corteza cerebral. RESULTADOS: En total se evaluaron 171 exploraciones de 107 pacientes (83 varones, 88 mujeres [incluyendo escaneos repetidos], edad media 8 años 10 meses, rango 1 año 1 mes - 34 años, DE 5 años 9 meses). El espesor medio cortical en esta cohorte fue de 2,78 mm (DS 0,17). Los hallazgos anteriores de papiledema (p=0,036) y de hidrocefalia (p=0,007) se asociaron de forma independiente con el adelgazamiento cortical. El grosor cortical no varió significativamente por sexo (p=0,534), síndrome (p=0,896), SAOS (p=0,464), CFO (p=0,375), o posición tonsilar (p=0,682). INTERPRETACIÓN: La detección de papiledema o hidrocefalia en la craneosinostosis sindrómica, se asocia con cambios significativos en el grosor cortical. Esto apoya la necesidad de estrategias de tratamiento preventivo en lugar de tratamientos reactivos.

Hipertensão intracrianiana e espessura cortical na craniossinostose sindrômica OBJETIVO: Avaliar o impacto de fatores de risco para hipertensão intracraniana (HIC) na espessura cortical em craniossinostose sindrômica. MÉTODO: Fatores de risco para HIC incluindo papiloedema, hidrocefalia, apnéia obstrutiva do sono (AOS), posição das tonsilas do cerebelo, idade de deflexão da curva da circunferência occipitofrontal (COF), e sexo foram coletados dos registros de pacientes com craniossinostose sindrômica (síndromes de Apert, Crouzon, Pfeiffer, Muenke, Saethre-Chotzen) e imagens. As imagens de ressonância magnética foram analisadas e exportadas para análise estatística. Um modelo linear misto foi desenvolvido para determinar correlações com mudanças na espessura do córtex cerebral. RESULTADOS: No total, 171 imagens de 107 pacientes (83 do sexo masculino, 88 do sexo feminino [incluindo varreduras repetidas], média de idade 8a 10m, variação 1a 1m-34a, DP 5a 9m) foram avaliados. A espessura cortical média nesta coorte foi 2,78mm (DP 0,17). Achados prévios de papiloedema (p=0,036) e de hidrocefalia (p=0,007) foram independentemente associados com a redução cortical. A espessura cortical não variou significativamente com o sexo (p=0,534), síndrome (p=0,896), AOS (p=0,464), COF (p=0,375), ou posição tonsilar (p=0,682). INTERPRETAÇÃO: A detecção do papiloedema ou hidrocefalia na craniossinostose sindrômica se associa com mudanças significativas na espessura cortical, sustentando a necessidade de estratégias de tratamento preventivas e não reativas.

Noncontact respiration monitoring techniques in young children: A scoping review.

Pediatric sleep-related breathing disorders, or sleep-disordered breathing (SDB), cover a range of conditions, including obstructive sleep apnea, central sleep apnea, sleep-related hypoventilation disorders, and sleep-related hypoxemia disorder. Pediatric SDB is often underdiagnosed, potentially due to difficulties associated with performing the gold standard polysomnography in children. This scoping review aims to: (1) provide an overview of the studies reporting on safe, noncontact monitoring of respiration in young children, (2) describe the accuracy of these techniques, and (3) highlight their respective advantages and limitations. PubMed and EMBASE were searched for studies researching techniques in children <12 years old. Both quantitative data and the quality of the studies were analyzed. The evaluation of study quality was conducted using the QUADAS-2 tool. A total of 19 studies were included. Techniques could be grouped into bed-based methods, microwave radar, video, infrared (IR) cameras, and garment-embedded sensors. Most studies either measured respiratory rate (RR) or detected apneas; n = 2 aimed to do both. At present, bed-based approaches are at the forefront of research in noncontact RR monitoring in children, boasting the most sophisticated algorithms in this field. Yet, despite extensive studies, there remains no consensus on a definitive method that outperforms the rest. The accuracies reported by these studies tend to cluster within a similar range, indicating that no single technique has emerged as markedly superior. Notably, all identified methods demonstrate capability in detecting body movements and RR, with reported safety for use in children across the board. Further research into contactless alternatives should focus on cost-effectiveness, ease-of-use, and widespread availability.

Evaluation of the OSA treatment protocol in syndromic craniosynostosis during the first 6 years of life.

INTRODUCTION: Obstructive sleep apnea (OSA) is frequently present in patients with syndromic craniosynostosis. The aim of this study is to determine the long-term effectiveness of our OSA treatment protocol in our tertiary center in a cohort of children with syndromic craniosynostosis. METHODS: Children with syndromic craniosynostosis born between January 2005 and December 2013 were eligible for inclusion (n = 114). Data from ambulatory and inhospital polysomnographies were used. The obstructive-apnea/hypopnea index was used for OSA classification. RESULTS: Polysomnographies were performed in 83 patients. Mild OSA was diagnosed in 19, moderate in six, and severe in seven children. Of the 32 patients with OSA, 12 patients (37.5%) initially received expectant care of which OSA resolved spontaneously in nine without recurrence. Twenty patients were surgically treated. Adenotonsillectomy (ATE) had a 90% success rate with no OSA recurrence. Monobloc surgery was performed in four patients with mild OSA, although not OSA-indicated. Monobloc was performed for moderate or severe OSA in six patients, in four patients in combination with ATE and with mandibular distraction in one. Monobloc surgery for moderate or severe OSA had a 100% success rate in treating OSA and decannulation. CONCLUSION: Expectant care is often sufficient to resolve mild OSA in patients with syndromic craniosynostosis, and should also be considered in patients with moderate OSA with close follow-up. ATE has an important role in the OSA treatment protocol. Monobloc surgery, combined with mandibular distraction on indication, is effective in resolving moderate to severe OSA with a stable long-term result.

Dural sinus volume in children with syndromic craniosynostosis and intracranial hypertension.

OBJECTIVE: Intracranial hypertension is a major concern in children with syndromic craniosynostosis (sCS). Cerebral venous hypertension caused by cerebral venous outflow obstruction is believed to contribute to intracranial hypertension. The authors therefore hypothesized that cerebral venous volume would be increased in those children with sCS and intracranial hypertension. METHODS: In a case series of 105 children with sCS, of whom 32 had intracranial hypertension, cerebral MRI techniques were used to quantify the volume of the superior sagittal sinus, straight sinus (StrS), and both transverse sinuses. RESULTS: Linear regression showed that total cerebral venous volume increased by 580.8 mm3 per cm increase in occipitofrontal head circumference (p < 0.001). No significant difference was found between the intracranial hypertension group and the nonintracranial hypertension group (p = 0.470). Multivariate ANOVA showed increased StrS volume (as a proportion of total volume) in the intracranial hypertension group (8.5% vs 5.1% in the nonintracranial hypertension group, p < 0.001). Multivariate logistic regression showed that a 100-mm3 increase in StrS volume is associated with increased odds of having intracranial hypertension by 60% (OR 1.60, 95% CI 1.24-2.08). CONCLUSIONS: Although intracranial hypertension was not associated with total cerebral venous volume increase, it was associated with an isolated increase in StrS volume. Hence, it is unlikely that general cerebral venous outflow obstruction is the mechanism of intracranial hypertension in sCS. Rather, these findings indicate either a central cerebral vulnerability to intracranial hypertension or a mechanism involving venous blood redistribution.

Improvement in Sleep Architecture is associated with the Indication of Surgery in Syndromic Craniosynostosis.

Children with syndromic craniosynostosis (sCS) often suffer from obstructive sleep apnea (OSA) and intracranial hypertension (ICH). Both OSA and ICH might disrupt sleep architecture. However, it is unclear how surgically treating OSA or ICH affects sleep architecture. The aim of this study was twofold: to explore the usefulness of sleep architecture analysis in detecting disturbed sleep and to determine whether surgical treatment can improve it. METHODS: Eighty-three children with sCS and 35 control subjects, who had undergone a polysomnography (PSG), were included. Linear-mixed models showed the effects of OSA and ICH on sleep architecture parameters. In a subset of 19 patients, linear regression models illustrated the effects of OSA-indicated and ICH-indicated surgery on pre-to-postoperative changes. RESULTS: An increase in obstructive-apnea/hypopnea index (oAHI) was significantly associated with an increase in N2-sleep, arousal index, and respiratory-arousal index and a decrease in REM-sleep, N3-sleep, sleep efficiency, and sleep quality. ICH and having sCS were not related to any change in sleep architecture. OSA-indicated surgery significantly increased the total sleep time and sleep efficiency and decreased the arousal index and respiratory-arousal index. ICH-indicated surgery significantly decreased REM-sleep, N1-sleep, sleep efficiency, and sleep quality. CONCLUSIONS: For routine detection of disturbed sleep in individual subjects, PSG-assessed sleep architecture is currently not useful. OSA does disrupt sleep architecture, but ICH does not. OSA-indicated surgery improves sleep architecture, which stresses the importance of treating OSA to assure adequate sleep. ICH-indicated surgery affects sleep architecture, although it is not clear whether this is a positive or negative effect.

Muenke syndrome: long-term outcome of a syndrome-specific treatment protocol.

OBJECTIVE: The authors evaluated the long-term outcome of their treatment protocol for Muenke syndrome, which includes a single craniofacial procedure. METHODS: This was a prospective observational cohort study of Muenke syndrome patients who underwent surgery for craniosynostosis within the first year of life. Symptoms and determinants of intracranial hypertension were evaluated by longitudinal monitoring of the presence of papilledema (fundoscopy), obstructive sleep apnea (OSA; with polysomnography), cerebellar tonsillar herniation (MRI studies), ventricular size (MRI and CT studies), and skull growth (occipital frontal head circumference [OFC]). Other evaluated factors included hearing, speech, and ophthalmological outcomes. RESULTS: The study included 38 patients; 36 patients underwent fronto-supraorbital advancement. The median age at last follow-up was 13.2 years (range 1.3-24.4 years). Three patients had papilledema, which was related to ophthalmological disorders in 2 patients. Three patients had mild OSA. Three patients had a Chiari I malformation, and tonsillar descent < 5 mm was present in 6 patients. Tonsillar position was unrelated to papilledema, ventricular size, or restricted skull growth. Ten patients had ventriculomegaly, and the OFC growth curve deflected in 3 patients. Twenty-two patients had hearing loss. Refraction anomalies were diagnosed in 14/15 patients measured at ≥ 8 years of age. CONCLUSIONS: Patients with Muenke syndrome treated with a single fronto-supraorbital advancement in their first year of life rarely develop signs of intracranial hypertension, in accordance with the very low prevalence of its causative factors (OSA, hydrocephalus, and restricted skull growth). This illustrates that there is no need for a routine second craniofacial procedure. Patient follow-up should focus on visual assessment and speech and hearing outcomes.

Pilot study of intracranial venous physiology in craniosynostosis.

OBJECTIVE In addition to craniocerebral disproportion, other factors, such as Chiari malformation type I, obstructive sleep apnea, and venous outflow obstruction, are considered to have a role in the occurrence of intracranial hypertension in craniosynostosis. This pilot study examined cerebral venous flow velocity to better characterize the complex intracranial venous physiology of craniosynostosis. METHODS The authors performed a prospective cohort study of craniosynostosis patients (n = 34) referred to a single national (tertiary) craniofacial unit. Controls (n = 28) consisted of children who were referred to the unit's outpatient clinic and did not have craniosynostosis. Transfontanelle ultrasound scans with venous Doppler flow velocity assessment were performed at the first outpatient clinic visit and after each surgery, if applicable. Mean venous blood flow velocities of the internal cerebral vein (ICVv) and the superior sagittal sinus (SSSv) were recorded and blood flow waveform was scored. RESULTS Preoperatively, SSSv was decreased in craniosynostosis patients compared with controls (7.57 vs 11.31 cm/sec, p = 0.009). ICVv did not differ significantly between patients and controls. Postoperatively, SSSv increased significantly (7.99 vs 10.66 cm/sec, p = 0.023). Blood flow waveform analyses did not differ significantly between patients and controls. CONCLUSIONS Premature closure of cranial sutures was associated with decreased SSSv but not ICVv; indicating an effect on the superficial rather than deep venous drainage. Further Doppler ultrasound studies are needed to test the hypothesis that at an early stage of craniosynostosis pathology SSSv, but not pulsatility, is abnormal, and that abnormality in both SSSv and the superficial venous waveform reflect a more advanced stage of evolution in suture closure.

Electrocardiographic variables in children with syndromic craniosynostosis and primary snoring to mild obstructive sleep apnea: significance of identifying respiratory arrhythmia during sleep.

BACKGROUND: In the spectrum of children with symptomatic sleep disordered breathing (SDB), some individuals - such as those with upper airway resistance syndrome (UARS) - do not have abnormalities on polysomnography (PSG). In this study we have assessed whether assessment of respiratory arrhythmia (RA) and heart rate variability (HRV) analysis helps in management of children with syndromic craniosynostosis and none-to-mild obstructive sleep apnea (OSA). METHODS: Prospective cohort study in children aged 1-18 years old with syndromic craniosynostosis. Children were selected for HRV analysis from the ECG if their obstructive apnea-hypopnea index (oAHI) was between zero and five per hour (ie, oAHI ≤5/hour). Subjects were divided into groups based on the presence or absence of respiratory arrhythmia (with or without RA respectively) using the electrocardiogram (ECG). The main analysis included studying the relationship between RA and HRV, symptoms, interventions, and sleep architecture. RESULTS: We identified 42 patients with, at worst, mild OSA. We found higher parasympathetic control and higher total power in children with RA during the non-rapid eye movement (non-REM) sleep. Children with RA also have a relatively higher percentage of paradoxical breathing during non-REM sleep (P = 0.042). Intracranial hypertension was distributed equally between groups. Last, RA patients showed increased parasympathetic activity that further increased in non-REM sleep. CONCLUSION: In syndromic craniosynostosis cases with SDB and PSG showing oAHI ≤5/hour, the presence of RA may indicate subsequent need for treatment interventions, and a trend toward higher occurrence of clinical symptoms. ECG analyses of HRV variables in subjects with RA demonstrate increased parasympathetic activity and total power. Such findings may add to the diagnosis of apparently asymptomatic children.

Sleep related breathing disorders and indications for polysomnography in preterm infants.

There is a range of breathing problems which occur and may persist in preterm infants, such as central apneas, obstructive apneas and periodic breathing. Preterm infants may also suffer from respiratory distress syndrome and chronic lung disease necessitating prolonged use of oxygen therapy after discharge from the hospital. Due to these persistent breathing pattern abnormalities in preterm infants, there is a higher risk of altered sleep and apparent life threatening events. Polysomnography can be a helpful tool to identify those infants who have abnormalities in their breathing pattern, to identify those infants who have an increased risk to get a sleep related breathing event at home and to decide about the discontinuation of oxygen therapy.

Effect of Preterm Birth on Echogenicity in Basal Ganglia.

In this study, the influence of prematurity on echogenicity of deep gray matter at 30-wk corrected age was assessed using ultrasound measurements. In an observational cohort study, ultrasound scans of 224 extremely preterm infants were prospectively collected. Gray values were assessed in putamen and globus pallidus. Intra- and inter-observer reliability was analyzed and showed excellent agreement. The globus pallidus to putamen ratio was significantly related to gestational age at birth, adjusted regression coefficient in points per wk: 1.28 (95% confidence interval [CI]: 0.38-2.19) for left and 2.12 (95% CI: 1.23-3.02) for right-side images. At 30-wk corrected age this was still the case, adjusted regression coefficient: 0.45 (95% CI: -0.57 to 1.47) for left and 1.29 (95% CI: 0.10-2.48) for right. The putamen is more hyperechoic with lower gestational age. Measuring ultrasound gray values in deep gray matter seems highly reproducible. Prematurity shows a negative correlation with echogenicity of the putamen, this persists at 30-wk corrected age, suggesting altered maturation.