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At least 991 records · Page 55Linked to original sources
PubMedDate not supplied

Sequential MRI findings in a patient with a germ cell tumor in the basal ganglia.

Serial changes of MRI scanning of an 11-year-old boy with hemiparesis due to a germ cell tumor in the basal ganglia are presented. Initial brain MRI T1-weighted images revealed a subtle mixed signal intensity lesion at left anterior and posterior limbs of the internal capsule. This lesion was not enhanced with Gd-DTPA, however, T2-weighted images showed a misty high signal intensity lesion in the same region. The MR images also showed hemiatrophy of the left basal ganglia. Histologic examination of biopsy specimens of the tumor revealed an embryonal carcinoma. The patient was treated with chemotherapy with subsequent improvement in the hemiparesis. Our case suggests that germ cell tumors must be considered in the differential disorders of lesions in the ipsilateral hemiatrophic basal ganglia in pediatric patients with hemiparesis.

Basal Ganglia↗
PubMedDate not supplied

Two possible cases of Alexander disease. Multimodal evoked potentials and MRI.

We describe two unrelated girls with slowly progressive leukodystrophy with macrocephaly. On MRI, both patients exhibited diffuse involvement of the cerebral white matter, excluding the internal capsule and optic radiation. Their visual-evoked potentials were normal. Short-latency somatosensory-evoked potentials exhibited the absence of early scalp components. Auditory brainstem responses in both patients showed intramedullary conduction disturbance. These MRI and electrophysiological findings are similar to those in infantile Alexander disease.

Adolescent↗
PubMedDate not supplied

123I-IMP SPECT findings in mitochondrial encephalomyopathies.

We performed N-isopropyl-[123I]p-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) in three patients with Leigh syndrome, two patients with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), and two siblings with progressive external ophthalmoplegia (PEO). The SPECT images were compared with the findings on magnetic resonance imaging (MRI) and computed tomography (CT). All Leigh syndrome patients showed low accumulation areas (LAA) bilaterally in the frontal lobes and the basal ganglia. The frontal lobe LAA was seen even in an area without abnormalities on CT/MRI. Each MELAS patient showed a focal LAA. SPECT could also detect an old stroke-like lesion that was no longer shown by CT/MRI. However, SPECT did not show LAA in the basal ganglia, which showed calcification on CT or abnormal signal intensity on MRI. MRI in the 2 PEO patients showed lesions bilaterally in the basal ganglia in one, and in the internal capsules in the other. SPECT showed LAA not only in corresponding areas, but also in the occipital lobes, where no lesions were revealed by MRI. Thus, 123I-IMP SPECT was more sensitive than CT/MRI for detecting stroke-like lesions in MELAS patients, although it did not detect small lesions in the basal ganglia. LAA in the frontal lobes and occipital lobes may be SPECT findings characteristic of Leigh syndrome and PEO, respectively.

Adolescent↗
PubMedDate not supplied

MR diffusion imaging in Pelizaeus-Merzbacher disease.

A case of classical type Pelizaeus-Merzbacher disease was reported. This patient exhibited marked motor and mental developmental delay, and nystagmus, with a positive familial history. Electrophysiological studies, such as on brainstem auditory evoked potentials, blink reflex and somatosensory evoked potentials, suggested marked disturbance of nerve conduction in CNS. T2-weighted magnetic resonance (MR) images revealed non-progressive diffuse T2 prolongation of cerebral white matter after a 2-year interval, indicating congenital hypomyelination in CNS. A newly developed magnetic resonance diffusion imaging method demonstrated the existence of diffusional anisotropy in the corpus callosum, internal capsule, and white matter of the frontal lobe. Although the diffusional anisotropy was considered to depend on the well-developed multiple layers of myelin around the axons, the imaging data of this patient demonstrated that the diffusional anisotropy did not necessarily depend on those multiple layers. These results may indicate the potential usefulness of MR diffusion imaging, combined with electrophysiological studies and conventional MR imaging, for analyzing the lesions of the cerebral white matter.

Anisotropy↗
PubMedDate not supplied

An MRI study of the myelination pattern in West syndrome.

Using magnetic resonance imaging (MRI), we studied the myelination of the brains of 8 patients with West syndrome. All cases were symptomatic, 2 having severe asphyxia, 1 lissencephaly, 1 Leigh encephalopathy, 2 tuberous sclerosis, 1 multiple anomalies and 1 microcephaly. Myelination of the pons, cerebellum, thalamus, internal capsules, optic radiation, centrum semiovale and cerebral white matter was separately assessed. The 2 cases with tuberous sclerosis exhibited normal myelination patterns, although asymmetry of the cerebral white matter was noted. These cases had a moderate degree of mental retardation and persistent seizures. The other 6 cases exhibited a marked delay of myelination throughout the central nervous system except for the midbrain. These cases had severe psychomotor retardation and persistent seizures. Although the difference in the outcome may simply reflect the different etiological disorders, these results suggest that the myelination pattern is related to the psychomotor retardation but not to the severity of the seizures in West syndrome. Atrophy of the corpus callosum developed during ACTH therapy and disappeared after the therapy. It was thus suggested that the callosal atrophy caused by the ACTH therapy was reversible.

Atrophy↗
PubMed1994

Pyramidal tract Wallerian degeneration and correlated symptoms in stroke.

In order to reveal the precise degree of injury in the pyramidal tract after stroke, we studied 35 patients with motor deficit associated with cerebrovascular disease of the internal capsule using the T2-weighted coronal image along the 'pyramidal line'. According to the severity of the motor deficit, the patients were divided into three groups. The Wallerian index was calculated as: (area of Wallerian degeneration in the pons divided by area of the ipsilateral half of the pons) x 100. There were significant differences between the three groups. It is concluded that the area of Wallerian degeneration is related to the severity of motor deficit.

Adult↗
PubMed1996

Reliability of brain structure morphometry in hydrocephalic children using MR images.

To assess the ability of human operators to make decisions about region boundaries in significantly malformed brains, we performed a study of the reliability of morphometric measurements of specific brain structures from MRI in children with hydrocephalus and controls. Cross-sectional area measures of the corpus callosum, internal capsules and centrum semiovale, and volumes of the lateral ventricles were made in 50 children. Independent measurements were made by two raters on T1 and T2-weighted MR images. Pearson's correlation coefficients (r) and intraclass correlation coefficients (ICC) between the two rater's sets of measures were computed for each structure across all subjects. ICCs ranged from a low of 0.7502 to a high of 0.9895. All ICCs were significant at the p < .0001 level and were generally less than or equal to the corresponding Pearson's r value in every case. Therefore, the Pearson's r may overestimate the reliability. The results of this study support the claim that the ICC should be used rather than the Pearson's r when assessing interater reliability in situations where large between-group differences are present. In addition, the results show that brains malformed by disorders, such as hydrocephalus, can be reliably assessed using morphometric measures of MR images.

Brain↗
PubMed1994

Computed tomographic findings after acute carbon monoxide poisoning.

Selective necrosis and degeneration of the globus pallidus are characteristic autopsy findings in patients with severe carbon monoxide (CO) poisoning. The objective of this study was to show that computed tomography (CT) may demonstrate these morphological changes in the brain during life, and provide a clue to prognosis. The authors reviewed the medical records of 19 consecutive patients with acute CO poisoning who underwent CT examination during hospitalization. Abnormal CT findings were found in 10 of the 19 patients (53%). The most common abnormal findings were low-density areas in the basal ganglia. These lesions were found in 7 of the 10 cases, and varied from small (limited to the globus pallidus) to large (extending to the internal capsule). Of the 10 patients with abnormal CT scans, 9 survived to hospital discharge but all had some degree of functional neurological impairment. Eighty-nine percent (8 of 9) of the patients with normal CT scans were discharged neurologically intact. Awareness of the potential for basal ganglia lesions in CO poisoning should lead to more accurate CT interpretation and may have significant prognostic implications.

Acute Disease↗
PubMed1988

Ontogeny of the dopamine and cyclic adenosine-3':5'-monophosphate-regulated phosphoprotein (DARPP-32) in the pre- and postnatal mouse central nervous system.

The ontogeny of a dopamine and cyclic adenosine-3':5'-monophosphate-regulated phosphoprotein with an apparent molecular weight of 32 kilodaltons (DARPP-32) has been studied in the central nervous system of the prenatal, newborn and adult mouse. DARPP-32-immunoreactive somata were first identified at day 12 of gestation, in the primary olfactory cortex and in the ventrolateral medulla oblongata. On day 14 of gestation, neurons containing DARPP-32-like immunoreactivity became apparent in the caudate nucleus, olfactory tubercle, nucleus accumbens, frontoparietal cortex and the ventral medulla oblongata. During the period up to and including birth, the number of cell bodies and fibres in all these areas increased markedly. In addition, DARPP-32-positive neurons became visible in the olfactory nucleus, the arcuate nucleus, and DARPP-32-positive cells appeared in the choroid plexus of the lateral, third and fourth ventricles. DARPP-32-containing fibres could be seen in the median eminence, the ventrolateral thalamus, and in the striatonigral projection, descending in the internal capsule to ramify extensively in the substantia nigra. Only in the cerebellum and suprachiasmatic nucleus did the development of DARPP-32-like immunoreactivity occur postnatally. The development of tyrosine hydroxylase, the rate-limiting enzyme for catecholamine synthesis, was simultaneously examined. The arrival of the tyrosine hydroxylase-containing projection to the caudate nucleus, the olfactory tubercle and the nucleus accumbens apparently occurred 1-2 days after the appearance of DARPP-32-immunoreactive cells within these regions. In the ventral and ventrolateral medulla oblongata, and the primary olfactory cortex, no tyrosine hydroxylase innervation was seen near the DARPP-32-positive neurons at days 12-14. The organization of the DARPP-32-containing somata of the caudate nucleus into aggregates of 5-15 neurons was partly paralleled spatially by an increased density of tyrosine hydroxylase-positive fibres. Many DARPP-32-immunoreactive cells in the immature mouse brain are present by the day of birth, particularly in the areas known to receive a dopaminergic innervation. The development of these presumptive dopaminoceptive DARPP-32-containing neurons does not seem to be dependent on the presence, however, of a dopaminergic input, since in all regions examined DARPP-32-LI preceded the appearance of tyrosine hydroxylase-like immunoreactivity by at least 1-2 days. Indeed, the results suggest that the existence of DARPP-32-like immunoreactivity in cell bodies and dendrites may be a pre-requisite for the formation or subsequent stabilization of dopaminergic synapses.

Aging↗
PubMed1991

Individual C6 glioma cells migrate in adult rat brain after neural homografting.

Cultured C6 glioma cells were prelabeled with the plant lectin Phaseolus vulgaris leuco-agglutinin (PHAL) and grafted as a cell suspension (10(6) cells in 5.0 microliters) into freshly made cortical implantation pockets in adult host rats. Animals were killed 1-21 days post-implantation (DPI). The brains were removed, dehydrated, embedded in paraffin and sectioned at 8 microns. Paraffin sections were processed for light level immunofluorescent double labeling for PHAL, a marker for graft derived cells, and glial fibrillary acidic protein (GFAP), a specific marker for C6 glioma cells and astrocytes. Cells positive for both PHAL and GFAP were graft-derived C6 cells. By 7 DPI a large mass developed which extended above the surface of the brain and invaded (displacement of host tissue by a cell mass) the host parenchyma. This mass increased in size over the next 14 days. The invading tumor mass contained double labeled cells at all time periods examined. In addition to the invasion process, grafted C6 cells spread through the host parenchyma by migration (movement of single cells). Individual graft-derived C6 (GFAP/PHAL positive) cells migrated into host cortex surrounding the implantation pocket, corpus callosum ventral to the implantation pocket, ipsilateral internal capsule and bilaterally in the habenula.

Animals↗
PubMed1992

NCAM as a differentiation marker of postmigratory immature neurons in the developing human nervous system.

The regional distribution and cellular localization of the neural cell adhesion molecule were investigated in the developing nervous system of human embryos and fetuses, by using immunocytochemistry with antibodies against the human neural cell adhesion molecule. Embryos and fetuses with crown-rump lengths ranging from 15 to 80 mm (corresponding approximately to 6-12 ovulation weeks) were examined. In the telencephalon, immunoreactivity was found in the primordial plexiform layer and in the early cortical plate. During later stages, immunoreactivity was present in the marginal zone, cortical plate, developing subplate zone and radiations of the internal capsule. In the mesencephalon and rhombencephalon, neuronal perikarya were outlined and strong staining was present in fiber bundles. In the spinal cord, strong immunostaining was present in fiber tracts and in dorsal and ventral roots. Immunostaining outlined perikarya of dorsal and ventral gray columns; the neuropil of the developing gray matter was also stained. Contrary to findings in some other species, precursor cells in the proliferating zones, i.e. all cells of ventricular zones and the external granular layer in the proliferation were not stained. Reactivity, however, was also observed in single mature-looking nerve cell bodies and their processes, which were localized in proliferating zones. All peripheral nervous structures including nerve fibers and peripheral nervous tissue components derived from the neural crest (i.e. sensory and autonomic ganglia) expressed the neural cell adhesion molecule. At the cellular level staining always appeared to be associated with the entire cell membrane of a given neuron including its outgrowing processes. Immunocytochemical staining for neural cell adhesion molecule is an excellent method for the identification of single nerve fibers, nerves and nerve cell bodies in situ in the developing peripheral and early central nervous system. The neural cell adhesion molecule is suggested as a marker of postmigratory immature neurons in the developing human nervous system.

Biomarkers↗
PubMed1993

Migration pathways, differentiation and survival of macroglial cells from a xenograft implanted into the thalamus of newborn mice.

Embryonic rabbit corpus callosum transplants were grafted into thalamus of newborn shiverer mice in order to compare the fates of oligodendroglial and astroglial cells derived from the transplants. Our model allowed the identification of the two populations of macroglial cells. The thalamus was chosen as site of implantation because of its situation at a crossroad of numerous neuronal fascicles. Previous studies, where the dorsal striatum was used as site of implantation, had shown that corpus callosum was one of the favorite routes of migration for both populations of macroglial cells. In the present study special attention was given to the comparison of the migration pathways and areas of settlement of implanted astroglia and oligodendroglia. The internal capsule, the medial lemniscus, the crus cerebri and the thalamic radiations were used by both populations of transplant derived macroglial cells for their migrations through the host parenchyma. They integrated into the host tissue on these routes or further away in areas such as the putamen, the mesencephalon or the colliculi. Signs of degeneration of the implanted astroglia were often observed after 1 month post-implantation.

Animals↗
PubMed1993

In vitro differentiation inhibits the migration of cultured neonatal rat cortical astrocytes transplanted to the neonatal rat cerebrum.

Neonatal rat astrocytes transplanted into the rat cerebrum migrate extensively. However, few of the molecular signals determining this migration have been defined. In the present study, in vitro modifications were designed to examine whether differentiation prior to transplantation would affect the magnitude or pattern of astrocyte migration in the neonatal host brain. Here, cortical astrocytes were collected from the brains of rats 1-3 days postpartum and purified by culturing them in DME medium supplemented with 10% calf serum. After 14-21 days, astrocytes were labelled with fluorescein-tagged latex microspheres for 16 hr; the label was then removed and replaced with either fresh medium or fresh serum-free medium plus 1 mM dbcAMP. After 48 hr, cells were harvested and then transplanted into the right frontal cerebrum of neonatal rats at 3 days postpartum by injection with a hand-held Hamilton syringe. Animals were sacrificed at 3, 6, 9, 15, 21 and 28 days after inoculation and their brains examined with fluorescence microscopy. Astrocytes not exposed to dbcAMP prior to implantation migrated along the corpus callosum, internal capsule, glial limitans, ventricular linings and the hippocampal structure. They also appeared to migrate in a radial fashion toward the periphery from the ventricular lining. Astrocytes treated with dbcAMP prior to transplantation did not appear to migrate into the neonatal parenchyma, remaining confined to the injection site for at least 6 days. Migration then appeared to commence at a normal rate after 9 days. Thus, neonatal cortical migrate outward in a pattern similar to that defined by the radial glia. Astrocytes differentiated by dbcAMP treatment, however, do not appear to migrate to any large degree in the neonatal brain until the treatment effect diminishes, suggesting that differentiation may represent an end-point to glial migration in the neonatal host brain.

Animals↗
PubMedDate not supplied

Cockayne syndrome: MRI correlates of hypomyelination.

Two siblings with Cockayne syndrome are reported who had most of the stigmata characteristic of the syndrome as it was initially described in 1936. Unusual findings are emphasized, such as the early onset of cataracts and the early detection of peripheral neuropathy. The previously reported autopsy abnormalities in this condition are correlated with the present magnetic resonance imaging findings of mild ventricular enlargement and delay in myelination of the cerebrum and cerebellum. Properly myelinated structures included the basal ganglia, thalamus, internal capsule, splenium, and genu of the corpus callosum.

Brain↗
PubMedDate not supplied

Varicella with delayed contralateral hemiparesis detected by MRI.

We report a 3 1/2-year-old boy who developed a hemiparesis 4 weeks after the onset of a varicella infection. In previously described cases of varicella with delayed contralateral hemiparesis, computed tomography typically revealed infarcts in the basal ganglia and internal capsule. To our knowledge, our patient is the first studied by magnetic resonance imaging. The pathogenesis of this syndrome may be a varicella zoster virus-related vasculopathy similar to that observed in herpes zoster ophthalmicus with delayed contralateral hemiparesis.

Chickenpox↗
PubMedDate not supplied

Magnetic resonance imaging in preterm infants.

Magnetic resonance imaging was performed in 9 preterm infants at 37-43 weeks postmenstrual age. They all were born at 26-35 weeks gestation. Myelination was graded according to its most cephalic location. Myelination pattern 2 (myelination observed in the posterior limb of the internal capsule and adjacent structures of the thalamus and lenticular nucleus) was demonstrated in 2 infants, pattern 3 (myelination of the corona radiata) in 3 infants, and pattern 4 (myelination of the centrum semiovale) in 4 infants. Bilateral low intensity areas were found on T1-weighted images in 7 infants and a ribbon-like, high intensity was observed in 5. These findings revealed a wide variety of magnetic resonance imaging appearance in apparently normal preterm infants. Caution is needed in interpreting the pathologic nature of such features in preterm infants during the perinatal period.

Asphyxia Neonatorum↗
PubMedDate not supplied

Prognosis and MRI after ischemic stroke of the basal ganglia.

The clinical courses and long-term prognoses in 16 young patients with infarctions of the basal ganglia were evaluated and the recent magnetic resonance imaging findings in 9 of them were examined. Only 5 of 14 patients (35%) had motor sequelae, 4 had hemiparesis, and 1 had gait disturbance. Secondary dystonia occurred in 1 patient. Magnetic resonance imaging disclosed a circumscribed lesion in the basal ganglia, as reflected by T2 high- and T1 low-intensity signals, in all patients. The abnormal region on T2-weighted images usually was more extensive than that observed on T1-weighted ones. The hemiplegic patients each had an area of abnormal intensity in the internal capsule or corona radiata with relatively high signals on the T2- and proton-density-weighted images. Mild to moderate asymmetric atrophy of the midbrain on the side ipsilateral to the stroke lesion was observed in 8 of 9 patients. The mechanism involved may be remote transsynaptic neuronal death of the substantia nigra, as well as Wallerian degeneration of the pyramidal tract.

Adolescent↗