Advanced serial CUS seems highly effective in diagnosing preterm brain injury, but may miss cerebellar abnormalities. Although MRI does identify these lesions, feasibility is limited. Improved safety, better availability and tailored procedures are essential for MRI to increase its value in clinical care.
BackgroundCerebral MRI performed on preterm infants at term-equivalent 30 weeks' gestational age (GA) is increasingly performed as part of standard clinical care.ObjectiveWe evaluated safety of these early MRI procedures.Materials and methodsWe retrospectively collected data on patient safety of preterm infants who underwent early MRI scans. Data were collected at fixed times before and after the MRI scan. MRI procedures were carried out according to a comprehensive guideline.ResultsA total of 52 infants underwent an MRI scan at 30 weeks’ GA. Although no serious adverse events occurred and vital parameters remained stable during the procedure, minor adverse events were encountered in 26 infants (50%). The MRI was terminated in three infants (5.8%) because of respiratory instability. Increased respiratory support within 24 h after the MRI was necessary for 12 infants (23.1%) and was significantly associated with GA, birth weight and the mode of respiratory support. Hypothermia (core temperature < 36°C) occurred in nine infants (17.3%). Temperature dropped significantly after the MRI scan.ConclusionMinor adverse events after MRI procedures at 30 weeks GA were common and should not be underestimated. A dedicated and comprehensive guideline for MRI procedures in preterm infants is essential.Electronic supplementary materialThe online version of this article (doi:10.1007/s00247-012-2426-y) contains supplementary material, which is available to authorized users.
RTFReaction time to fixation AIM Children born extremely preterm are at risk of visual processing problems related to brain damage. Damage in visual pathways can remain undetected by conventional magnetic resonance imaging (MRI) and functional consequences cannot always be predicted. The aim of this study was to assess the efficacy of processing visual information in infants born extremely preterm at a corrected age of 1 year using a communication-free visual function test based on eye tracking.
METHOD
RESULTSThe infants in the preterm group had longer response times in detecting colour patterns (red-green) and motion compared with infants in the comparison group. No impairments were detected in oculomotor functions (saccades, pursuit, and fixations).
INTERPRETATIONThe data suggest that delays in processing visual information can be identified in children born extremely preterm. The delays might be ascribed to deficits in neuronal connectivity in visual pathways at a microstructural level.With increasing numbers of preterm births and increasing survival rates, 1 there is a growing recognition that a substantial number of infants born preterm will develop longterm neurodevelopmental problems related to cognitive and neurosensory performance.2 Encephalopathy of prematurity includes various lesions, such as periventricular leukomalacia, which is often the result of hypoxia-ischemia and affects white matter around the lateral ventricles. 3,4
SUMMARY:Diffusion tensor imaging is a valuable measure in clinical settings to assess diagnosis and prognosis of neonatal brain development. However, obtaining reliable images is not straightforward because of the tissue characteristics of the neonatal brain and the high likelihood of motion artifacts. In this review, we present guidelines on how to acquire DTI data of the neonatal brain and recommend high-quality data acquisition and processing as an essential means to obtain accurate and robust parametric maps. Sudden head movements are problematic for DTI in neonates, and these may lead to incorrect values. We describe strategies to minimize the corrupting effects both in terms of acquisition (eg, more gradient directions) and postprocessing (eg, tensor estimation methods). In addition, tools are described that can help assess whether a dataset is of sufficient quality for further assessment.
ABBREVIATIONS:MD ϭ mean diffusivity; FA ϭ fractional anisotropy; RESTORE ϭ robust estimation of tensors by outlier rejection; TBSS ϭ tract-based spatial
Advances in neonatal neuroimaging have improved detection of preterm brain injury responsible for abnormal neuromotor and cognitive development. Increasingly sophisticated MR imaging setups allow scanning during early preterm life. In this review, we investigated how brain MR imaging in preterm infants should be timed to best predict long-term outcome. Given the strong evidence that structural brain abnormalities are related to long-term neurodevelopment, MR imaging should preferably be performed at term-equivalent age. Early MR imaging is promising because it can guide early intervention studies and is indispensable in research on preterm brain injury.
BACKGROUND AND PURPOSE:Neonatal DTI enables quantitative assessment of microstructural brain properties. Although its use is increasing, it is not widely known that vast differences in tractography results can occur, depending on the diffusion tensor estimation methodology used. Current clinical work appears to be insufficiently focused on data quality and processing of neonatal DTI. To raise awareness about this important processing step, we investigated tractography reconstructions of the fornix with the use of several estimation techniques. We hypothesized that the method of tensor estimation significantly affects DTI tractography results.
BackgroundTo study early neurodevelopment in preterm infants, evaluation of brain maturation and injury is increasingly performed using diffusion tensor imaging, for which the reliability of underlying data is paramount.ObjectiveTo review the literature to evaluate acquisition and processing methodology in diffusion tensor imaging studies of preterm infants.Materials and methodsWe searched the Embase, Medline, Web of Science and Cochrane databases for relevant papers published between 2003 and 2013. The following keywords were included in our search: prematurity, neuroimaging, brain, and diffusion tensor imaging.ResultsWe found 74 diffusion tensor imaging studies in preterm infants meeting our inclusion criteria. There was wide variation in acquisition and processing methodology, and we found incomplete reporting of these settings. Nineteen studies (26%) reported the use of neonatal hardware. Data quality assessment was not reported in 13 (18%) studies. Artefacts-correction and data-exclusion was not reported in 33 (45%) and 18 (24%) studies, respectively. Tensor estimation algorithms were reported in 56 (76%) studies but were often suboptimal.ConclusionDiffusion tensor imaging acquisition and processing settings are incompletely described in current literature, vary considerably, and frequently do not meet the highest standards.Electronic supplementary materialThe online version of this article (doi:10.1007/s00247-015-3307-y) contains supplementary material, which is available to authorized users.
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