Biomedical subjects

H M Liu

Publications and source records attributed to H M Liu.

189 records · Page 11Linked to original sources

PubMedDate not supplied

Application of Fluid-Attenuated Inversion Recovery pulse sequence in children with tuberous sclerosis.

To evaluate the application of Fluid-Attenuated Inversion Recovery (FLAIR) pulse sequence to increase the sensitivity of detecting tubers in tuberous sclerosis patients compared with fast spin-echo T2-weighted (FSET2W) image, we obtained 12 magnetic resonance (MR) images in 10 patients (mean age = 57.7 months old). Among the 12 examinations, 114 cortical and 128 subcortical tubers were revealed on the FLAIR images, whereas 54 and 72 tubers were found respectively on the FSET2W images. This may be due to the FLAIR pulse sequences remarkably attenuated CSF signals in comparison with the FSET2W images. However, FSET2W image delineated more subependymal nodules than FLAIR imaging did. Gd-DTPA enhanced T1W image is the most suitable pulse sequence to detect giant cell astrocytoma near the foramen of Monro. The results in cases of infants and little children were similar.

Child↗

PubMedDate not supplied

Ultrastructure of the nervous system.

Within the nervous system, five cell types were studied by the electron microscope: the neuron, astrocyte, oligodendroglia, microglia and ependymal cells. The neurons are characterized by the Nissl substance within the perikaryon, the neurotubules and the neurofilaments. The three types of glial cells can be distinguished from one another. The astrocyte has relatively lucent cytoplasm and contains filaments which extend into long cytoplasmic processes. The oligodendroglia has electron-dense cytoplasm with thin extensions wedged between the cellular processes of the neuropil. The microglia cytoplasm is similar to the oligodendroglia but can be differentiated by the peculiar convoluted outline of the nuclear membrane and the clear space which separate the nucleus from the cytoplasm. The ependymal cell has characteristic microvilli and cilia at its ventricular surface. The cytoplasm contain parabasal bodies and tight junctions between adjacent cells. In the peripheral nerve, the axon and the myelin sheath are located within the Schwann cells. The terminal nerve endings from enlargements filled with synaptic vesicles. Electron microscopy of the nervous system is not only essential for research, but is also helpful in diagnosis of certain diseases.

Astrocytes↗

PubMedDate not supplied

Intracerebral arteriovenous fistula: report of one case.

Intracranial arteriovenous fistula (AVF) is rare. Of the 320 arteriovenous malformations (AVMs) treated by Halbach over the past ten years, only five (1.6%) had a single arteriovenous connection. In the present study, a male infant developed focal seizure and intracranial hemorrhage without cardiac decompensation at the age of 42 days. When he was 3 years and 4 months old, status epileptics occurred, and AVF was discovered via CT scan and cerebral angiographic examination. The AVF was fed by a middle cerebral artery and drained into a huge cortical vein over the left parietooccipital area. Endovascular therapy and/or surgery were suggested, but the family refused. Though seizures occurred occasionally, the patient's consciousness level had become more clear, and he was discharged after three weeks' hospitalization. The patient was noted to be lethargic and only could roll over partially at the age of 3 year and 8 months, in the latest follow-up.

Arteriovenous Fistula↗

PubMedDate not supplied

Moyamoya disease manifested initially by repeated attacks of adversive seizure: report of one case.

A nine-year-old Chinese boy had suffered from recurrent episodes of adversive seizure for about a year, seizures which affected the left upper limb, with his head and eyes turning toward the left. An acute attack of left upper-limb weakness and central-type facial palsy occurred before his consultation. Cranial computed tomography (CT) revealed infarction of the right frontoparietal area, and increased density in the head of the left caudate nucleus. Cerebral angiographic study demonstrated a typical pattern of moyamoya disease with bilateral stenosis of the supraclinoid portion of internal carotid arteries. Encephaloduroarteriosynangiosis with encephalomyosynangiosis were performed twice, with resulting good patency of blood flow observed in the follow-up angiographic study.

Child↗

PubMedDate not supplied

Multiple sclerosis in children: clinical, neuroimaging, and neurophysiological correlations.

Four female children with clinically-definite diagnoses of multiple sclerosis (MS) were studied with multimodal evoked potentials (EPs), electroencephalogram (EEG), cerebrospinal fluid (CSF) analysis, computed tomography (CT) and magnetic resonance imaging (MRI). Correlations among the clinical features, neuroimaging and neurophysiological studies were also evaluated. Their ages of the onset ranged from 5 to 11 years. The clinical evolution in the all four MS cases was relapsing-remitting form. MRI studies in three cases showed abnormal demyelinating plaques in the brainstem, cerebellum and white matter of the cerebrum. CT examination, performed in the other MS case, did not reveal hypodensic lesion. Despite that MRI failed to document optical nerve lesions, three cases had abnormal visual evoked potentials (VEPs). Somatosensory evoked potentials (SSEPs) were abnormal in three cases. Brainstem auditory evoked potentials (BAEPs) were abnormal in two cases presenting with signs of brainstem dysfunction. The conclusion was that paraclinical evidences obtained from MRI and multimodal evoked potential studies are of value as an aid in localizing involved areas and detecting silent lesions in children with MS.

Adolescent↗

PubMedDate not supplied

Growth retardation as the initial manifestation of intracranial tumors: report of two cases.

Two boys (9 years and 14 years old) were brought to visit our pediatric endocrine clinic with the chief complaint of short stature. Because of growth retardation, they were admitted for further evaluation. Physical examinations, including neurological examinations, were unremarkable but the laboratory examination confirmed the diagnosis of hypopituitarism in both patients. Skull radiography examinations showed some calcifications at suprasellar regions in the case 1 but negative findings in case 2. Furthermore, computed tomography (CT) of the head of case 2 performed at an outside hospital half a year before was reported to be normal, so case 2 fits the conventional diagnosis of idiopathic hypopituitarism. However, magnetic resonance image (MRI) study of the head disclosed that both of them are victims of an intracranial tumor, craniopharyngioma and germ cell tumors respectively. After surgical intervention, followed by radiotherapy, both patients were stable without any neurological deficit. Our experience confirmed that an MRI study of sellar region is warranted in search of the etiology of hypopituitarism.

Adolescent↗

PubMedDate not supplied

Suprasellar embryonal carcinoma: report of one case.

Intracranial embryonal carcinoma is a rare germ cell tumor found predominantly in the pineal region and, to a lesser extent, in the suprasellar region. The case of a 12-year-old female with a history of secondary amenorrhea for 6 months is reported; her symptoms included decreased visual acuity, dizziness and postprandial vomiting over a 1-month period. A huge suprasellar mass was found by computed tomography. Serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (beta-HCG) levels were elevated. The tumor was subtotally resected; pathologic and immunocytochemical findings were compatible with embryonal carcinoma. The patient died three weeks after operation. The case is described and pertinent literature is reviewed.

Brain Neoplasms↗

PubMedDate not supplied

Acute disseminated encephalomyelitis in children: clinical, neuroimaging and neurophysiologic studies.

Nine patients below 20 years of age (4 males and 5 females), who were diagnosed to have acute disseminated encephalomyelitis (ADEM) by clinical findings and magnetic resonance imaging (MRI), were reviewed retrospectively. They ranged from 4 months to 20 years of age with an average of 8.6 years. Seven patients (78%) received neurophysiological studies, which included electroencephalography, multimodality evoked potentials (EPs), nerve conduction velocity and/or F-wave measurement. The presentation symptoms were mainly headache, vomiting, consciousness change and motor deficits. Seven (78%) of nine patients had symptoms preceded by fever or upper respiratory tract infections; one (11%) was preceded by trivalent mumps, measles, rubella vaccination and no definite predisposing factor was found in another. Computed tomography (CT) scans were abnormal in five (71 %) of seven children, while MRI showed multiple lesions in seven (78%) of nine children. The lesions in MRI were mainly in the brainstem (n = 6), basal ganglion (n = 5), thalamus (n = 4), periventricular white matter (n = 4) and cerebellum (n = 4). EPs disclosed spinal cord involvement in all patients who received the examination. Peripheral neuropathy was disclosed in one patient. It was concluded that associated radiculoneuropathy is possible in patients with ADEM. Both MRI and neurophysiologic studies are complementary for diagnosis of ADEM.

Adolescent↗

PubMedDate not supplied

Magnetic resonance imaging in symptomatic/cryptogenic partial epilepsies of infants and children.

In order to identify the brain lesions of symptomatic/cryptogenic partial epilepsies (S/CPEs) in infants and children, magnetic resonance imaging (MRI) studies, thorough encephalographic (EEGic) studies, and detailed clinical and neurologic evaluations were obtained in 300 infants and children who were diagnosed to have S/CPEs with onset before the age of 13 years during the past 7 years. The overall detection rate of brain lesions by MRI was 41.7% (125/300). Congenital malformations (18 cases), vascular malformations (9 cases), neurocutaneous syndromes (13 cases), and space-taking lesions (20 cases) constitute a large percentage of SPEs in infants and children. A variety of insults such as infection, ischemia, hemorrhage, trauma and metabolic disorders can result in destructive parenchymal loss lesions including porencephaly, focal atrophy, hemiatrophy, and diffuse brain atrophy (20 cases). Major etiologic factors leading to infarction, encephalomalacia, leukomalacia, included trauma, hvpoxicischemic encephalopathy (HIE), systemic lupus erythematosus (SLE), encephalitis, vasculitis, venous thrombosis, vasculopathies, and heart problems (22 cases). Mesial temporal sclerosis (MTS) could be evidenced in around 20% (18/95) of cases with temporal lobe epilepsy (TLE), which was strongly associated with past histories of febrile seizures and encephalitis complicated by status epileptics. However, cases with porencephaly, global atrophy or delayed myelination of unilateral temporal lobe on MRI were more related to HIE. With the advent of neuroimaging techniques, particularly MRI, a wide variety of underlying pathology can be detected as a cause of symptomatic partial epilepsies in pediatric patients. The occurrence of S/CPE indicates the presence of localized brain dysfunction, and many of the causes are potentially treatable. An orderly and thorough clinical and laboratory investigations, as well as neuroimaging studies should be made to diagnose and treat any underlying conditions.

Adolescent↗