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Biomedical subjects

Renate Swarte

Publications and source records attributed to Renate Swarte.

5 recordsLinked to original sources

Postnatal onset cortical dysplasia associated with infarction of white matter.

On MRI at 35 weeks of a boy born at 25 weeks, focal disorganization of the cortex was observed near a frontal venous infarct developed in the first week. Disruption of the final steps of cell migration, injury to the subplate and/or disruption of corticospinal axons are possible mechanisms behind it. Preterms with white matter lesions at or below 25 weeks postconceptional age should be scrutinized for cortical dysplasia.

Cerebral Cortex↗

Bacillus cereus meningoencephalitis in preterm infants: neuroimaging characteristics.

BACKGROUND AND PURPOSE: Meningoencephalitis can severely damage the developing brain. Preterms are more prone for nosocomial infections with pathogens other than Group B streptococci and Escherichia coli. In this report we focus on the deleterious clinical course and imaging characteristics of proven Bacillus cereus meningoencephalitis. METHODS: We collected 3 cases of proven Bacillus cereus meningoencephalitis. In the medical records we focused on prenatal, perinatal, and postnatal risk factors. Imaging data of several brain ultrasounds, MR images, and diffusion-weighted images were reevaluated. RESULTS: The ultrasound and MR images show a typical pattern of mainly hemorrhagic and early cavitating, selective white matter destruction. CONCLUSION: Knowledge of this paradigm of acquired brain injury may help to better understand the natural course of these severe neonatal infections.

Bacillus cereus↗

Sonographic appearance of the normal and abnormal insula of Reil.

Three planes are discerned during ultrasonographic screening of the insula in parasagittal view: opercular, insular, and fissural. Six newborn infants with normal brain anatomy, including two each of 28, 34, and 40 weeks' gestation, were selected for a description of the evolution of these parasagittal planes. Opercularization of the insula begins to be detected on a sonogram at about the 24th gestational week and progresses cranially. On coronal section the insular space forms a shallow groove at 24 weeks, becoming a slit at 28 weeks that grows longer and develops branches after 32 weeks. At 28 weeks the ascending anterior branch of the circular groove and the lateral fissure at the bottom of the insula are clearly seen in parasagittal section. Subsequent change consists of undulation and bifurcation of the lateral fissure, together with elongation of the anterior margin. Secondary gyri become visible in the insular dome between 28 and 34 weeks, forming short anterior and long posterior insular gyri. Five term newborn infants with perisylvian polymicrogyria were observed with both neonatal ultrasound and magnetic resonance imaging: two of unknown cause, and one each due to cytomegalovirus, bifunctional peroxisomal protein deficiency, and monozygous twinning. With polymicrogyria, on parasagittal sonographic examination at fissural level the anterior margin of the circular groove is a short rudiment. In insular view, only rudimentary sulci ascend from the lateral fissure; short and long gyri are not seen. In opercular view, no secondary branches are seen from the lateral fissure, an image akin to that seen at 28 weeks. A complete insular triangle is not recognized in any of these sections. A deep abnormal sulcus may prolong the lateral fissure when schizencephaly is associated with polymicrogyria. The insula in glutaric aciduria type II has no secondary gyri at term and is reduced to a simple and small triangle. Not all instances of polymicrogyria lead to macroscopically recognizable alteration of insular gyri.

Brain Diseases↗

Changes in globus pallidus with (pre)term kernicterus.

OBJECTIVE: We report serial magnetic resonance (MR) and sonographic behavior of globus pallidus in 5 preterm and 3 term infants with kernicterus and describe the clinical context in very low birth weight preterm infants. On the basis of this information, we suggest means of diagnosis and prevention. METHODS: Charts and MR and ultrasound images of 5 preterm infants and 3 term infants with suspected bilirubin-associated brain damage were reviewed. Included were preterm infants with severe hearing loss, quadriplegic hypertonia, and abnormal hypersignal of globus pallidus on T2-weighted MR imaging (MRI). In 1 infant who died on day 150, the diagnosis was confirmed during the neonatal period. The others were picked up as outpatients and scanned at 12 or 22 months' corrected age. Three instances of term kernicterus were included for comparison of serial MRI in the neonatal period and early infancy: they were caused by glucose-6-phosphate dehydrogenase deficiency, urosepsis, and dehydration plus fructose 1-6 biphosphatase deficiency. RESULTS: Five preterm infants of 25 to 29 weeks' gestational age presented with total serum bilirubin (TSB) levels below exchange transfusion thresholds commonly advised. Mixed acidosis was present in 3 infants around the TSB peak. The bilirubin/albumin molar ratio was >0.5 in all, in the absence of displacing drugs. All failed to pass bedside hearing screen tests and had severe hearing loss on auditory brain response testing. Symmetrical homogeneous hyperechogenicity of globus pallidus was the alerting feature in 1 infant. Globus pallidus was hyperintense on T1-weighted MR images in this child. The other infants presented with severe developmental delay as a result of dyskinetic quadriplegia and hearing loss. Globus pallidus was normal on T1- but hyperintense on T2-weighted MR images at 12 or 22 months' corrected age. Subthalamic involvement was documented in coronal fluid attenuated inversion recovery MRI in 2 infants. The term infants with classical clinical presentation in the neonatal period had MR behavior similar to the preterms, but pallidal injury was not recognized with targeted sonographic examination. Their neonatal MR images demonstrated pallidal T1 hyperintensity and mild T2 hyperintensity. CONCLUSION: Acidotic very low birth weight preterm infants with low serum albumin levels develop MR-confirmed pallidal injury and hearing loss facing "accepted" TSB levels. Serial MRI documents a shift from acute mainly T1 hypersignal to permanent T2 hypersignal in globus pallidus within the late neonatal period. Subthalamic and not thalamic involvement helps to differentiate from ischemic or metabolic disorder. As newborns, these infants are rigid and have severe apnea, before developing hypertonic quadriplegia in infancy.

Echoencephalography↗