Female, 10 months old, with status epilepticus, refractory seizures, prior history of hypoglycemia, ex 26 week premature with history of volvulus and short-gut syndrome. Since the prior examination, substantial generalized parenchymal volume loss has occurred. All of the supratentorial lobes are affected to some degree, though the parietal regions do seem to be slightly more prominently affected. As a result of this volume loss, the lateral and third ventricles demonstrate a dilated morphology and the cerebral sulci are diffusely widened. The pattern of white matter myelination is delayed, compatible with prematurity, and with no convincing evidence of interval maturation.On diffusion weighted images, a very subtle bilateral and symmetric pattern of restricted diffusion is seen suggesting cytotoxic edema involving the parietal and occipital regions predominantly, but also the remaining lobes to a lesser degree. The basal ganglia are spared but there is some questionable subtle involvement of the posterior medial thalami as well.On postcontrast imaging, and particularly on the postcontrast FLAIR sequences, small gyriform areas of enhancement are evident indicating breakdown of the blood-brain barrier in the medial parietal lobes, right side more than left. No other definite pathologic intracranial enhancement is seen.Single voxel spectroscopy was performed on the discretely enhancing right parietal lesion showing a marked reduction in the quantity of NAA as well as above-normal levels of lipid and a discrete moderate lactate presence. Single voxel spectroscopy was also performed on an area of parietal white matter which was free of discrete signal abnormality, and this also shows significant reduction in NAA and the presence of both lipid and lactate. Single voxel spectroscopy of the left basal ganglia shows a modest reduction in NAA but no convincing evidence of lipid or lactate.Dedicated imaging of the pituitary gland is within normal limits. The gland itself is normal in size and morphology. No discrete lesions are seen. The posterior pituitary is identified in its normal position. The pituitary stalk is midline and both the stalk and the gland show homogeneous enhancement.
Findings on this examination indicate significant brain parenchymal injury with generalized volume loss predominantly affecting the white matter, as well as evidence of neuronal injury and loss. These changes have developed in the time interval since the prior examination at which point the brain appeared normal accounting for prematurity. Dedicated imaging of the pituitary is within normal limits.Although the parenchymal abnormalities are generalized, there is a slight preference for the posterior regions of the brain. In these areas, in addition, there is evidence of an ongoing or very recent pathologic process in the form of mild vasogenic edema and mild localized breakdown of the blood-brain barrier.Spectroscopic assessment over multiple areas of the brain demonstrates significant reduction in the level of NAA which indicates neuronal injury and loss. Moderately abnormal levels of lipid, which indicates cell membrane breakdown, and lactate, which indicates failure of energy metabolism, are also seen both in areas of blood brain barrier breakdown and in white matter which is free of significant signal abnormality. The presence of lactate also supports the likelihood of an ongoing or recent pathologic process as it is typically a transient finding after a parenchymal insult. Of note, no convincing lipid or lactate is detected in the basal ganglia.Taking into account the complex clinical course of this patient, a single unifying diagnosis cannot be made on the basis of this examination. One possibility is that the marked parenchymal changes reflect evolving hypoglycemic injury, and indeed the pattern of parenchymal involvement is supportive of this. Seizures may therefore be secondary to this injury. Alternately, ongoing seizure activity can itself induce some of the observed imaging findings including cytotoxic edema, blood brain barrier breakdown, and elevations of lactate. Finally, the possibility of an underlying inherited metabolic disorder does remain, though on the basis of this single examination it is felt to be less likely.The presence of ongoing seizure activity does complicate the interpretation of the imaging findings. If seizures can be controlled, there may be some benefit to repeating the imaging including spectroscopy after 1-2 weeks seizure-free.