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Biomedical subjects

D Prayer

Publications and source records attributed to D Prayer.

At least 37 records · Page 2Linked to original sources
PubMed2002

Familial combined pituitary hormone deficiency caused by PROP-1 gene mutation. Growth patterns and MRI studies in untreated subjects.

BACKGROUND: Mutations of the prophet of PIT-1 (PROP-1), a paired-like homeodomain transcription factor which is responsible for early embryonic pituitary development, have recently been reported as a cause of combined pituitary hormone deficiency. METHODS: We describe the phenotype, long-term auxological data and MRI findings in two families with 4 affected members, all of whom have a mutation of the PROP-1 gene. GH, TSH, PRL, LH and FSH were completely deficient in all patients. RESULTS: ACTH deficiency was not diagnosed until the 3rd or 4th decades of life. Pituitary MRI showed an empty sella in 2 subjects, but unspecific tissue accumulation resembling a pituitary mass lesion in another patient. The affected boy from family II who was continuously treated with all the necessary hormones reached the familial target height. However, the 3 subjects in family I were only treated sporadically (GH treatment lasting from 1 to 3 years). CONCLUSION: Despite this insufficient therapy, final height was in the lower normal range. Longitudinal growth continued up to the age of 40 years in these subjects.

Adolescent↗
PubMed2002

Auxological, ophthalmological, neurological and MRI findings in 25 Austrian patients with septo-optic dysplasia (SOD). Preliminary data.

UNLABELLED: Septo-optic dysplasia (SOD) comprises ophthalmological, endocrinological and neurological disorders resulting from varying degrees of midline malformation of the forebrain like visual impairment by optic nerve hypoplasia, endocrine deficits due to hypothalamic and/or pituitary anomalies, and psychomental retardation by associated cortical malformation. MRI shows aplasia/hypoplasia of the septum pellucidum and corpus callosum as a radiological hallmark. For etiology, genetic defects (Hesx1/HESX1 gene) as well as vascular disruption during embryonic brain development are discussed. AIM: To perform detailed analysis of morphological findings and clinical symptoms and to improve care of SOD patients by interdisciplinary management. PATIENTS: We investigated 25 patients with a mean age of 5.1 years at diagnosis. RESULTS: Pituitary insufficiency was present in 11/25 patients, multiple deficits in 6 of them. Bilateral optic nerve hypoplasia was found in 70% of patients, unilateral in 20%. Mild or moderate neurological disorders were observed in the majority of patients (14/20), EEG was usually normal (12/19). Analysis of MRI films revealed very heterogeneous morphological anomalies, ranging from isolated agenesis of the septum pellucidum to multiple malformations, involving the cortex. Malrotation of the hippocampal structures was a common finding. CONCLUSION: We conclude that only interdisciplinary management of SOD patients can ameliorate the exact diagnosis and outcome, depending on early visual or developmental support as well as early diagnosis and substitution of potentially life-threatening endocrine deficits.

Abnormalities, Multiple↗
PubMed2001

Combined prenatal ultrasound and magnetic resonance imaging in two fetuses with suspected arachnoid cysts.

Sonography and ultrafast magnetic resonance imaging were used in the prenatal assessment of two fetuses with sonographically suspected arachnoid cysts. In one case magnetic resonance imaging confirmed the ultrasound diagnosis, in the other case magnetic resonance imaging revealed the presence of a midline cyst associated with dysgenesis of the corpus callosum. Ultrafast magnetic resonance imaging is a useful supplementary imaging method in the evaluation of pregnancies complicated by fetal cerebral anomalies.

Adult↗
PubMed2001

Long-term MRI observations of childhood-onset relapsing-remitting multiple sclerosis.

PURPOSE: Long-term MRI follow-up of childhood-onset relapsing-remitting multiple sclerosis (RRMS) was carried out in 4 cases. MRI findings were correlated with clinical course and characteristic differences from adult-onset RRMS were elaborated. METHODS: Two girls and one boy with true childhood-onset, and one girl with juvenile-onset RRMS underwent 5-16 MRI examinations within 6-8 years. The total number of lesions, the numbers of new, active, disappearing and reappearing lesions, infratentorial and U-fibre lesions, "giant" plaques and "black holes" were counted. Callosal atrophy and general brain atrophy were assessed. The findings were related to the physical status according to the Expanded Disability Status Scale (EDSS). RESULTS AND CONCLUSIONS: Results showed that the primary differences in childhood-onset RRMS compared to adult-onset RRMS lie in the lack of, or slower development of irreversible changes ("black hole" formation, brain atrophy). Despite callosal atrophy and intensive U-fibre region involvement, school performance was unchanged. Regarding the frequency of "giant" lesions, an even more pronounced white matter involvement was found in our children compared to adults. All children exhibited a rather "benign" disease course. A more intensive remyelination, less severe neuronal loss, and higher functional brain plasticity at younger ages may account for these differences.

Atrophy↗
PubMed2001

Gamma knife radiosurgery of recurrent central neurocytomas: a preliminary report.

OBJECTIVES: A series of three recurrent central neurocytomas treated by gamma knife radiosurgery (GKRS), which were initially totally resected, are described. Up to now, no reports exist on this treatment modality for this rare tumour entity. METHODS: Three male patients, aged between 20 and 25 years, presented with large intraventricular tumours. Total tumour removal was achieved by a single surgical procedure (one patient) or two operations (two patients). Neuropathological investigation showed a central neurocytoma, immunohistochemically all three tumours expressed a neuronal antigenic profile typical for neurocytomas, and the MIB-1 proliferation index ranged from 2.4% to 8.7%. Each patient experienced a tumour recurrence after 5 to 6 years. The recurrence was multifocal in two and a singular tumour mass in one patient. Gamma knife radiosurgery was performed. The tumours were enclosed within the 30% to 60% isodoseline, and delivered a tumour marginal dose of 9.6 to 16 Gy. During the follow up period, the patients were tested clinically and the volume of the tumours was measured on MRI. RESULTS: Within follow up periods of 1 to 5 years, control MRI showed a significant decrease of the tumour mass in all cases. None of the patients developed new neurological symptoms after GKRS. Two patients returned to work in their previous employment, whereas one patient remained permanently disabled due to a pre-existing visual impairment and abducens palsy. CONCLUSION: GKRS proved to be a useful tool in the treatment of recurrent central neurocytomas. Tumour control and even tumour shrinkage can be achieved with a single procedure and a low risk of morbidity.

Adult↗
PubMed2001

Visualization of nonstructural changes in early white matter development on diffusion-weighted MR images: evidence supporting premyelination anisotropy.

BACKGROUND AND PURPOSE: Previously, we showed that diffusion-weighted MR imaging depicts evidence of directionally preferential water motion in white matter structures of developing rat brain before and after myelination, and considerably earlier than conventional imaging strategies. Present data augment these imaging and corresponding histologic findings with electron-microscopic corroboration. We additionally report the findings of a 10-day-old rat pup tested functionally by administration of the sodium-channel blocker, tetrodotoxin. METHODS: In two rat pups, drawn from the population reported previously, MR estimates of diffusion anisotropy of the optic nerves and chiasm were compared with histologic and electron microscopy results. To test the hypothesis that "premyelination" directional preference of water motion in white matter structures relates to sodium-channel activity, MR imaging was performed in a 10-day-old rat pup treated with the sodium-channel blocker, tetrodotoxin, and findings were compared with data from an age-matched control. RESULTS: Although diffusion anisotropy was present in optic structures of the youngest animal, myelin-sensitive histologic staining did not show myelin before 12 days; electron microscopy confirmed lack of any myelin or its precursors during the earliest maturational stage. Administration of tetrodotoxin to the 10-day-old rat-pup led to loss of diffusion anisotropy. CONCLUSION: Our findings provide two pieces of supporting data for the hypothesis that nonstructural changes are responsible for early anisotropic diffusion: electron microscopy shows no evidence of myelin despite diffusion anisotropy, and inhibiting the sodium-channel pump appears to remove the directional preference of water motion. Visualization of nonstructural "premyelination" consequences with diffusion-weighted imaging emphasizes its sensitivity and potential in studying early processes of brain development.

Aging↗
PubMed2001

[Acute head trauma: diagnostic imaging].

Computed tomography (CT) ist the primary modality of choice for imaging patients with acute head trauma. Lesions of the soft tissues and of the bones can be assessed more precisely than with other imaging modalities. With magnetic resonance imaging (MRI) additional information may be gained especially in subacute and chronic posttraumatic conditions. Urgent indication to perform a CT examination depends on the patient's history and on the mechanism of trauma. Image interpretation has been performed in the context of typical pathologic effects of trauma and with respect to potential therapy.

Acute Disease↗
PubMed2000

[123I]beta-CIT SPECT in multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration.

Differentiation between Parkinson's disease (PD) and other neurodegenerative disorders with parkinsonian features, such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), is difficult on clinical grounds. We studied the pattern of dopaminergic degeneration in 18 patients with probable MSA, 8 patients with PSP, 4 patients with CBD, 48 patients with PD and a similar degree of disability, and 14 control subjects performing single photon emission computed tomography (SPECT) 20 hours after injection of [123I]beta-CIT. Overall striatal binding was significantly reduced in MSA (-51% of normal mean), PSP (-60%), CBD (-35%), and PD (-58%), without overlap with control values. Asymmetry of striatal beta-CIT binding was significantly increased in patients with CBD and PD, as compared with control subjects. Although asymmetry seemed to be less pronounced in MSA and PSP than in PD, this was not statistically significant. Putamen-caudate nucleus ratios in patients with PD, MSA, and PSP, but not with CBD, were significantly reduced, as compared with control subjects. In conclusion, [123I]beta-CIT SPECT reliably enables the visualization of the presynaptic dopaminergic lesion in patients with MSA, PSP, and CBD. In most patients, however, it does not seem to be possible to differentiate these disorders from PD with this method.

Adult↗
PubMed2000

[Applications of cerebral MRI in neonatology].

Magnetic resonance tomography (MRT) has become the most important method in the workup of infantile cerebral complications after primary sonography. Cerebral MR examination and image interpretation during the infantile period require extensive knowledge of morphological manifestations, their pathophysiological background, and frequency. The choice of imaging parameters and image interpretation is demonstrated in infarctions and hemorrhages of the mature and immature brain. A review of the main differential diagnoses is also given. The relevance of MR spectroscopy and fetal MRI is discussed.

Brain↗
PubMed2000

[Diagnostic imaging in neonatal stroke].

UNLABELLED: A cerebral artery infarction is an important differential diagnosis in the newborn with neurological abnormalities. Based on clinical data, its incidence is estimated to be 1 in 4000 newborns. Since the course is often subclinical, the true incidence is probably higher. DIAGNOSIS: Cerebral ultrasound and Doppler sonography as readily available screening tools play a central role in the initial diagnosis of neonatal cerebral infarction. Definitive diagnosis is made by computed tomography or magnetic resonance imaging. Beside symptomatic anticonvulsive therapy, treatment aims at the prevention of secondary ischemic injury. DISCUSSION: Three term infants with different clinical courses of neonatal stroke are presented to sensitize the clinician and the radiologist for this probably underdiagnosed entity. The role of imaging modalities in the diagnosis and follow-up of neonatal cerebral infarction is discussed.

Brain Damage, Chronic↗
PubMed2000

Evidence of therapeutic efficacy of CCNU in recurrent choroid plexus papilloma.

A pregnant 33-year old woman developed nystagmus and cerebellar ataxia. A tumor in the roof of the fourth ventricle was diagnosed. The tumor was subtotally removed using microneurosurgical techniques. The histopathological diagnosis was choroid plexus papilloma (CPP). Twenty-one months later, the tumor recurred and was reoperated. Histologically the tumor displayed now increased mitotic activity and pleomorphism. Radiation therapy of the neuroaxis was performed. Within 59 months, the CPP recurred 3 more times with neuroradiological evidence of extensive spinal seeding. After several palliative irradiations, including 2 gamma-knife boosts, the patient was referred to chemotherapy. She was treated with CCNU (Lomustin) 100 mg/m2 orally (12 cycles, cumulative dosis 1440 mg/m2). Within 42 months, there was no new local recurrence and spinal seeding showed significant regression. Clinically the patient improved and stabilized, but needs continuous support because of persisting severe gait ataxia. The course of disease in our patient provides evidence for therapeutic efficacy of CCNU in recurrent CPP.

Adult↗
PubMed1999

Application of correlation dimension and pointwise dimension for non-linear topographical analysis of focal onset seizures.

For many patients who are candidates for epilepsy surgery, non-invasive evaluation fails to provide sufficient information to permit surgical treatment. Since there are also definite risks and considerable costs associated with invasive procedures, new (non-invasive) techniques are required. This study provides empirical evidence that a non-linear approach applied to ictal surface electroencephalograms (EEGs) can help to delineate the area of seizure onset and may prove useful in complementing visual analysis of the EEG. Multichannel EEGs, recorded from eight patients with different drug-resistant localisation-related epilepsies, were analysed using the concept of correlation dimension and two extensions based on the pointwise dimension. The latter also provided results in cases where assessment of the correlation dimension was not feasible. Comparative values between 2 and 6 were accepted as the result of the algorithms, mostly 3-4 for the EEG channels strongly reflecting epileptic activity, and 4-6 for the other signals. The proportion of accepted pointwise values was usually 200-800% for strong epileptic EEG activity compared to the other data. The approach permitted the characterisation of the scalp area reflecting epileptic activity. The results obtained were in perfect concordance with those obtained during pre-surgical work-up and confirmed by the post-operative outcome.

Adolescent↗
PubMed1999

Virchow-Robin spaces in childhood migraine.

Virchow-Robin spaces (VRS) are pia-lined extensions of the subarachnoid space which surround penetrating arteries as they enter the brain on its surface. Using high-resolution MRI, which shows small penetrating arteries, we studied a possible association of accentuated VRS in children with tension-type headache (TTH) or migraine. We studied 58 children aged 3-14 years (mean 10.8 years) with a clinical diagnosis of migraine (31) or TTH (27), who underwent cerebral MRI, and 30 headache-free patients of the same age (mean 10.2 years) and 30 adult migraineurs with postpubertal onset of symptoms, who served as controls. The images were reviewed for structural abnormalities in the regions of the small penetrating arteries. Accentuated VRS were found in 61% of the children with migrainous headaches and in 22% of children of those with TTH. Prominent VRS were seen in 27% of the control children and in only 13% of the adults. Small infarcts and gliosis were rare in children with or without headache, but were seen in 30% of the adult migraineurs. Our findings show that accentuated VRS are significantly more common in children with migraine than in those with TTH or headache-free controls. Detection of accentuated VRS may therefore enhance differential diagnosis of primary headaches in children, contributing to an improvement in management.

Adolescent↗
PubMed1999

Regional cerebral blood flow during temporal lobe seizures associated with ictal vomiting: an ictal SPECT study in two patients.

PURPOSE: Ictal vomiting represents a rare clinical manifestation during seizures originating from the temporal lobes of the nondominant hemisphere. The precise anatomic structures responsible for generation of ictal vomiting remain to be clarified. Ictal single photon emission computed tomography (SPECT), which allows one to visualize the three-dimensional dynamic changes of regional cerebral blood flow (rCBF) associated with the ongoing epileptic activity, should be useful to study the brain areas activated during ictal vomiting. METHODS: We performed ictal Tc-HMPAO SPECT scans in two patients with mesial temporal lobe epilepsy (MTLE) whose seizures were characterized by ictal retching and vomiting. MTLE was documented by typical clinical seizure semiology, interictal and ictal EEG findings, hippocampal atrophy on magnetic resonance imaging (MRI) scan, and a seizure-free outcome after selective amydalohippocampectomy. In both patients, seizures originated in the nondominant temporal lobe. We obtained accurate anatomic reference of rCBF changes visible on SPECT by a special coregistration technique of MRI and SPECT. We used ictal SPECT studies in 10 patients with MTLE who had seizures without ictal vomiting as controls. RESULTS: In the two patients with ictal vomiting, we found a significant hyperperfusion of the nondominant temporal lobe (inferior, medial, and lateral superior) and of the occipital region on ictal SPECT. In patients without ictal vomiting, on the contrary, these brain regions never were hyperperfused simultaneously. CONCLUSIONS: Ictal SPECT provides further evidence that activation of a complex cortical network, including the medial and lateral superior aspects of the temporal lobe, and maybe the occipital lobes, is responsible for the generation of ictal vomiting.

Adult↗
PubMed1998

Central nervous system disease in Langerhans cell histiocytosis.

Central nervous system (CNS) disease in Langerhans cell histiocytosis (LCH) is a poorly understood complication of yet unknown frequency. By far the most common manifestation is in the hypothalamic-pituitary system with diabetes insipidus as the leading sign, followed by other endocrinopathies and hypothalamic dysfunction. However, essentially all other parts of the CNS may be involved. On the one hand, space-occupying histiocytic infiltrates may lead to size- and site-depending symptoms, extending from adjacent bone lesions or arising from the meninges or choroid plexus. On the other hand, a progressive neurological deterioration can occur with mainly cerebellar-pontine symptoms. In this article, these clinical patterns are described in correlation with the morphology on MR imaging and histopathology. Further, the therapeutic strategies are reviewed critically, and guidelines for the management of patients with LCH-related CNS disease are presented.

Central Nervous System↗
PubMed1997

Diffusion-weighted MRI of myelination in the rat brain following treatment with gonadal hormones.

Previous studies have demonstrated the ability of high-resolution diffusion-weighted MRI to show maturation of white-matter structures in the developing rat brain. The purpose of this study was to investigate the influence of gonadal steroid hormones on the rate of this development. Starting from their second postnatal day, 16 rat-pups of either sex were repeatedly treated with subcutaneous implants containing 17-beta estradiol or delta-androstene 3,17 dione, respectively. Serial T1-, T2- and diffusion-weighted MRI was performed weekly for 8 weeks using a 4.7 T unit. Maturation of anterior optic pathways and hemisphere commissures was assessed. Diffusion-weighted images were processed to produce "anisotropy index maps", previously shown to be sensitive to white-matter maturation. Compared with untreated rat-pups, estrogen-treated animals showed accelerated, and testosterone-treated animals delayed maturation on anisotropy index maps and histological sections. In all animals, maturational changes appeared earlier on anisotropy index maps than on other MRI sequences or on myelin-sensitive stained sections. Diffusion-weighted imaging, and the construction of spatial maps sensitive to diffusion anisotropy, seem to be the most sensitive approach for the detection of maturational white-matter changes, and thus may hold potential for early diagnosis of temporary delay or permanent disturbances of white-matter development.

Androstenediol↗