Magnetic resonance imaging at term and neuromotor outcome in preterm infants

In order to evaluate the value of neonatal brain magnetic resonance imaging (MRI) for predicting neuromotor outcome in very low birthweight (VLBW) preterm infants, 51 such infants with gestational age <34 wk underwent brain MRI at term age. Myelination, parenchymal lesions (haemorrhage, leukomalacia, infarction, reduction of white matter), parenchymal lesions without subependymal haemorrhage, ventricular/brain ratios and widths of the extracerebral spaces were assessed. The MRI findings were compared with cranial ultrasound (US) performed at term. Infants' neuromotor development was followed up until 18 mo corrected age. Parenchymal lesions seen in MRI at term predicted cerebral palsy (CP) with 100% sensitivity and 79% specificity, the corresponding figures for US being 67% and 85%, respectively.
Parenchymal lesions in MRI, excluding subependymal haemorrhages, predicted CP with a sensitivity of 82% and a specificity of 97%, the corresponding figures for US being 58% and 100%, respectively. Delayed myelination, ventricular/brain ratios and widths of the extracerebral spaces failed to predict CP. Term age is a good time for neuroradiological examinations in prematurely born high-risk infants. Parenchymal lesions seen in MRI are reliable predictors for CP.     

高危晚期早产儿脑病临床特点及磁共振影像学评估

目的了解高危晚期早产儿(LPI)脑病的危险因素、临床特点及磁共振(MRI)影像学变化。方法对2009年1月至2014年12月住院且存在脑损伤高危因素的LPI,进行头颅MRI检查,分析LPI脑病危险因素、临床特点及头颅MRI特征。结果完成MRI检查的LPI共1 007例,影像学符合早产儿脑病患儿313例(31.1%)。LPI脑病中白质损伤占76.7%。LPI脑病的发生与胎龄无相关性,但随着出生体重增加,脑病检出率逐渐增高(P0.05)。Logistic回归分析结果显示:复苏史是早产儿脑病发生的独立危险因素(P0.01)。结论早产儿脑病在高危LPI中亦较常见,特别是脑白质损伤。复苏病史是LPI脑病的独立危险因素,需引起重视。     

Safety of magnetic resonance imaging in preterm infants

Aim: As we progress in our knowledge of preterm brain injury, cohort studies are focusing in neuroimaging preterm infants in the first days of life. Magnetic resonance (MR) is the most powerful neuroimaging modality and valuable in understanding perinatal brain injury. The main purpose of the study is to evaluate the safety of MR imaging in very low birth weight (VLBW) infants at our hospital settings where the scanner is located at some distance from the neonatal intensive care unit (NICU). Subjects and methods: This is a prospective study of 33 VLBW infants who underwent early MR imaging (MRI), within 10 days after birth and term corrected age MRI. The study period included June to December 2008. Results: A total of 46 MRI were performed on 33 preterm infants. The mean total time the infants stayed in the bore of the magnet was 13.04 min. No incidences occurred during transfer or during the scans, and no significant changes were found in heart rate, oxygen saturation and temperature. Conclusions: At our hospital settings, the process of transport and MR imaging have been proven to be safe and not to disturb any of the variables measured. MRI should not be restricted to centres with neonatal MR system or MR‐compatible incubator, as long as the process is coordinated and supervised by a multidisciplinary team.     

Physiological stability of preterm infants during magnetic resonance imaging

Aim: This study looked for evidence of physiological disturbance in preterm infants undergoing magnetic resonance imaging (MRI). Methods: Intensive care was continued, as appropriate, throughout scanning in each infant. The heart rate, oxygen saturation (SaO₂), temperature and mean arterial blood pressure (BP) was monitored during MRI in preterm infants, median gestational age at birth 27 (range 23–32) weeks and median postnatal age at initial MRI, 3 days (range 1–42). The acoustic noise level during imaging was also measured. Results: 2087 min of data were obtained from 39 examinations in 23 infants. The median heart rate was 159 and no bradycardia <100 or tachycardia >200 bpm occurred. Although 42 episodes of desaturation <90% were detected only three were <80, and these occurred in one infant due to endotracheal tube blockage. The median axillary temperature was 36.9°C (range 35.7–37.8) and median BP (n=6) was 37 mmHg (24–48). The ambient noise level in the MR system during scanning was 67–72 dBA. Conclusion: In preterm infants who required intensive care during scanning, MRI could be performed without major physiological instability.     

Magnetic resonance imaging of the brain in a cohort of extremely preterm infants.

To define magnetic resonance imaging (MRI) appearances of the brain in extremely preterm infants between birth and term, a sequential cohort of infants born at a gestational age <30 weeks was studied with a dedicated neonatal magnetic resonance scanner. Images of infants (n = 41) with a median gestational age of 27 weeks (range 23 to 29 weeks) were initially obtained at a median age of 2 days (range 1 to 20 days) and then repeatedly studied; 29 (71%) infants had MRI at a median gestational age of 43 weeks (range 38 to 52 weeks) (term MRI). On the initial MRI scan 28 of 41 infants had abnormalities: either intraventricular hemorrhage, germinal layer hemorrhage, ventricular dilatation, or diffuse and excessive high signal intensity in the white matter on T(2)-weighted images. When magnetic resonance images for preterm infants at term gestation were compared with those of infants in the control group born at term, 22 of 29 infants had dilatation of the lateral ventricles, 24 of 29 had squaring of the anterior or posterior horns of the lateral ventricles, 11 of 29 had a widened interhemispheric fissure or extracerebral space, and 22 of 29 had diffuse and excessive high signal intensity in the white matter. There were no cases of cystic periventricular leukomalacia. We conclude that MRI abnormalities are commonly seen in the brain of preterm infants on whom images are obtained within 48 hours of birth and that further abnormalities develop between birth and term. A characteristic appearance of diffuse and excessive high signal intensity in the white matter on T(2)-weighted images is associated with the development of cerebral atrophy and may be a sign of white matter disease. These MRI appearances may help account for the high incidence of neurodevelopmental impairment in extremely preterm infants.     

Investigation of lung disease in preterm infants using magnetic resonance imaging

Many preterm infants require ongoing respiratory support despite treatment with exogenous surfactant. The reasons for this are unclear, but may involve one or a combination of changes in water content or distribution within the lung. Detailed three-dimensional information with the potential to provide quantitation of water content may help to investigate this further. We aimed to determine if magnetic resonance (MR) imaging could be developed to study lung disease in preterm infants. Appropriate MR sequences and procedures were defined and we found that T1 and proton density weighted images could be successfully acquired. The images contained three-dimensional information that could not be obtained using chest radiograph. MR imaging may be a useful method for studying the pathology of respiratory distress syndrome and chronic lung disease in preterm infants.     

Magnetic resonance imaging in preterm infants

MR imaging of the premature infant poses a number of challenges with regard to safety, sequence optimization and recognition of the normal appearances of the developing brain. In this paper we discuss these challenges, and review the common intracerebral abnormalities associated with premature birth. Although the outcome for very-low-birth-weight babies has improved over the last decade, there remains a significant risk of subsequent development of neurological disability. The relationship between MRI abnormalities and long-term outcome is considered.     

晚期早产儿和早期足月儿1岁时神经心理发育水平的随访研究

目的 探讨晚期早产儿和早期足月儿1岁时的神经心理发育水平。方法 选择矫正年龄为1岁的1 257名儿童为研究对象。根据其出生时胎龄分为4组：早期早产儿（胎龄28~33⁺⁶周）、晚期早产儿（胎龄34~36⁺⁶周）、早期足月儿（胎龄37~38⁺⁶周）及完全足月儿（胎龄39~41⁺⁶周）。采用Gesell发展量表评估其神经心理发育水平,比较各组儿童在1岁时神经心理发育状况。结果 4组儿童1岁时5大能区（适应性、大运动、精细动作、语言、个人社交）发育商的差异均有统计学意义（P < 0.05）,且均表现为完全足月儿 > 早期足月儿 > 晚期早产儿 > 早期早产儿的趋势（P < 0.05）;各能区发育迟缓率也均表现为完全足月儿最低,早期早产儿最高（P < 0.05）。与完全足月儿相比,早期足月儿适应能力发育落后的风险增加（OR=1.796,P < 0.05）;晚期早产儿适应能力和精细动作发育落后的风险较高,OR值分别为2.651、2.679（P < 0.05）;早期早产儿适应能力、精细动作和个人社交能力发育落后的风险较高,OR值分别为4.069、3.710、3.515（P < 0.05）。结论 儿童1岁时神经心理发育落后的风险随出生胎龄的增加而降低,呈现剂量反应效应。早期足月儿和晚期早产儿仍然存在不同程度的发育落后,应重视早期足月儿和晚期早产儿的保健随访。     

Neurologic examination of preterm infants at term age: comparison with term infants

OBJECTIVES: The aim was to establish the range of neurologic findings in preterm infants reaching term age, their relation to gestational age at birth, and the possible differences with healthy term newborns tested during the first days of life. STUDY DESIGN: The Dubowitz neonatal neurologic examination was performed at term age in 157 low-risk preterm infants born between 25 and 34 weeks' gestation who had cranial ultrasonograms that were normal or showed minor abnormalities. Infants were subdivided in 3 groups according to their gestational age at birth. RESULTS: Within the preterm cohort, the range of scores for the 3 gestational age subgroups was different from each other for 21 of the 34 items, although the median scores were different only in 10 of the 34 items. The range of scores and their median in preterm infants however was wider than that found in term infants. Preterm infants examined at term were also more hyperexcitable and tended to have less flexor tone in the limbs and less extensor tone in the neck in the sitting posture. CONCLUSIONS: The distribution of scores provides useful guidelines when a preterm infant is examined at term.     

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目的 探讨早期、晚期早产儿与足月儿呼吸窘迫综合征(RDS)的发病趋势和临床特征的差异,为临床合理诊治提供依据。方法 2006年1月至2010年12月在郑州大学第三附属医院住院的963例RDS患儿根据胎龄不同分为早期早产儿组(<34周)679例,晚期早产儿组(34～<37周)204例,足月儿组(≥37周)80例,分别对各组患儿的发病率、入院情况、高危因素、临床诊治、预后及并发症进行比较。结果 RDS的发病率逐年增加,均以早期早产儿占多数,晚期早产儿和足月儿RDS比例有增多趋势;RDS患儿男婴超过女婴(P<0.05),且胎龄和体重越大,男婴比例越高;足月儿RDS组产前糖皮质激素使用率明显低于早产儿组;早产儿发生RDS的高危因素主要有胎膜早破、胎盘异常、母亲妊娠高血压疾病,足月儿发生RDS的高危因素主要是择期剖宫产与感染;晚期早产儿与足月儿RDS的临床诊断和应用肺泡表面活性物质(PS)时间均晚于早期早产儿;足月儿RDS应用机械通气比例明显高于早产儿,其临床治愈率高(P<0.05),在死亡率方面与早产儿组无差别;但并发气胸的比例高于早产儿组(P<0.05)。结论 新生儿呼吸窘迫综合征(NRDS)发病率逐年增高,晚期早产儿和足月儿RDS比例有增多趋势;早期、晚期早产儿与足月儿RDS在性别比例、高危因素、起病特点、治疗反应与并发症方面均存在差异,RDS的诊治需要考虑胎龄因素。足月儿RDS多与择期剖宫产、感染有关,发病相对较晚,容易合并气胸,应引起足够重视。     

Magnetic resonance and ultrasound brain imaging in preterm infants

Cranial ultrasonography has been used to identify brain injury in preterm neonates for more than two decades. More recently, magnetic resonance imaging has been used to evaluate brain development and pathology in these infants. In this review we describe how well findings from these two imaging modalities agree with histology findings and neuro-developmental outcome. In addition, we discuss studies comparing ultrasound and magnetic resonance imaging findings.     

振幅整合脑电图联合头颅磁共振定量指标对中晚期早产儿近期神经发育预测价值的前瞻性研究

目的 探讨振幅整合脑电图（amplitude-integrated electroencephalogram,aEEG）、头颅磁共振成像（cranial magnetic resonance imaging,cMRI）的定量指标双顶径（biparietal width,BPW）、两半球间距（interhemispheric distance,IHD）与中晚期早产儿近期神经发育的关系。 方法 前瞻性选择2018年9月至2020年4月入住新生儿重症监护病房的104例中晚期早产儿为研究对象,在生后72 h内采用Naqeeb法及睡眠-觉醒周期（sleep-wake cycling,SWC）进行aEEG评估;在矫正胎龄37周时完成cMRI检查,并在T2冠状位测量BPW和IHD;矫正月龄6月龄时采用0~6岁儿童发育筛查测验（Developmental Screening Test for Child Under Six,DST）随访神经发育,并根据发育商（development quotient,DQ）分为DST正常组（≥85分,78例）和DST异常组（DQ<85分,26例）,分析比较两组间各指标差异,以及aEEG和cMRI的关系。 结果 DST异常组aEEG正常率、SWC成熟率低于DST正常组（P<0.05）;与DST正常组相比,DST异常组的IHD偏大、BPW偏小（P<0.05）。不成熟的SWC、aEEG异常、较大的IHD是DST异常的危险因素（P<0.05）,较大的BPW是DST异常的保护因素（P<0.05）。 结论 中晚期早产儿生后72 h内的aEEG、矫正胎龄37周时cMRI定量指标BPW和IHD可能影响其矫正月龄6月龄时的神经发育结局。