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Biomedical subjects

W Reith

Publications and source records attributed to W Reith.

At least 55 records · Page 3Linked to original sources

[Glomus tumors of the head-neck-region].

Glomus tumors of the head and neck are rare tumors of adulthood which arise from paraganglia or glomus cells within the carotid glomus, vagus nerve, middle ear or jugular foramen. The diagnosis of these mostly benign lesions is predominantly done with CT and MRI. DSA can provide important additional information. Besides surgical resection, one therapy option is radiological intervention with tumor embolisation. Because of the typical radiological imaging and the "salt and pepper appearance" in MRI, glomus tumors can be differentiated from other lesions in the head and neck. This review gives a survey of the classification, diagnosis and therapy of paragangliomas with images to demonstrate characteristic features.

Glomus Tumor↗

[Proximal protection systems using carotid artery stent].

Controversies as to whether or not a protection device should be used in carotid artery stenting exist. Currently three temporary cerebral protection devices are being used. These are devices with distal balloon occlusion or filtration baskets and proximal occlusion devices with flow reversal in the internal carotid artery. This article focuses on flow reversal systems and aims to give some advice as to which patients could benefit from their use.

Angioplasty, Balloon↗

[Treatment of arteriosclerotic carotid stenosis: an overview].

Endarterectomy for extracranial carotid stenosis has proven to be the method of choice for symptomatic patients suffering from ischemia (NASCET, ECST). The effectivity of the operation for asymptomatic stenosis seems to be likely since the publication of the first results of the ACST trial. The safety and efficiency of carotid stenting has not been proven so far and has to be evaluated in randomized trials comparing surgery and endovascular treatment. We provide an overview of the current trials and try to define the role of carotid stenting.

Angioplasty, Balloon↗

[Technique and approach to carotid stenting].

Assuming that the ongoing large randomized controlled trials comparing CAS and endarterectomy support the efficacy and safety of CAS, this method will play a major role in patients with carotid stenosis in the near future. Patient selection, establishing standards of treatment, and systematic training of the interventionist are major issues. This article aims to give an overview of current techniques and devices available in CAS.

Angioplasty, Balloon↗

[Differential diagnosis of space demands in the cerebellopontine angle].

Most of the space demands in the cerebellopontine angle lie extra-axially. Important structures run within the cisterns of the cerebellopontine angle, such as the trigeminal, facial and vestibulocochlear nerves as well as the anterior inferior and posterior inferior cerebellar arteries and the veins which lead to the petrosal sinus. The most common space demands are caused by acoustic neuromas, meningeomas, vascular ectasia and aneurysms. Less common are epidermoid and other schwannomas as well as metastases, paragangliomas and arachnoidal cysts. Intra-axial tumours in the area of the cerebellopontine angle include the medulloblastoma, astrocytoma and the ependymoma, which occurs predominantly in children, in addition to the uncommon choroid plexus papilloma. Nearby, there are also space demands around the petrous bone, such as cholesterol granuloma, malignant otitis media, paraganglioma and metastases. For differential diagnosis, an understanding of the space requirements of the tumours in the cerebellopontine angle is needed in addition to knowledge of the anatomical structures.

Brain Stem Neoplasms↗

[Spinal intradural tumors].

Spinal intradural tumors are uncommon lesions but may cause significant morbidity. In establishing the differential diagnosis for a spinal lesion, location, age, and the patient's clinical presentation are important. Magnetic resonance imaging plays a central role in the visualization of spinal tumors, easily allowing tumors to be classified as extradural, intradural extramedullary, or intramedullary which is very useful in tumor characterization. We describe intradural tumors; the majority is extramedullary, with nerve sheath tumors being the most frequent. Intramedullary tumors are uncommon spinal tumors. Ependymomas and astrocytomas comprise the majority of this group. Typical imaging features of both intradural extramedullary and intramedullary tumors are described.

Humans↗

Regional variations in the thickness of cervical spine endplates as measured by computed tomography.

PURPOSE: To determine regional variations in the thickness of human cervical spine endplates with high spatial resolution. MATERIAL AND METHODS: Six explanted human cadaveric spine specimens underwent computed tomography (CT) scanning. Measurement of endplate thickness was done fully automatically at every point of the endplate using a computer program written specifically for this purpose. Variations in thickness along sagittal and coronal lines were determined and statistical parametric mapping was used to test for significant regional variations at every point. RESULTS: Anterior and medial aspects of superior endplates were shown to be significantly thinner than lateral and dorsal parts. Superior endplates were found to be thicker than inferior endplates. CONCLUSION: Fully automatic assessment of endplate thickness from CT data is feasible. Central regions of the cervical spine endplates are thinner than peripheral parts of the endplates. This distribution is more pronounced in superior than in inferior endplates.

Algorithms↗

The transcription factor RFX3 directs nodal cilium development and left-right asymmetry specification.

There are five members of the RFX family of transcription factors in mammals. While RFX5 plays a well-defined role in the immune system, the functions of RFX1 to RFX4 remain largely unknown. We have generated mice with a deletion of the Rfx3 gene. RFX3-deficient mice exhibit frequent left-right (LR) asymmetry defects leading to a high rate of embryonic lethality and situs inversus in surviving adults. In vertebrates, specification of the LR body axis is controlled by monocilia in the embryonic node, and defects in nodal cilia consequently result in abnormal LR patterning. Consistent with this, Rfx3 is expressed in ciliated cells of the node and RFX3-deficient mice exhibit a pronounced defect in nodal cilia. In contrast to the case for wild-type embryos, for which we document for the first time a twofold increase in the length of nodal cilia during development, the cilia are present but remain markedly stunted in mutant embryos. Finally, we show that RFX3 regulates the expression of D2lic, the mouse orthologue of a Caenorhabditis elegans gene that is implicated in intraflagellar transport, a process required for the assembly and maintenance of cilia. In conclusion, RFX3 is essential for the differentiation of nodal monocilia and hence for LR body axis determination.

Animals↗

[White matter alterations in neurodegenerative and vascular dementia].

Due to a significant overlap of the two syndromes, differentiation of degenerative dementia of the Alzheimer-type from vascular dementia may be difficult even when imaging studies are available. White matter changes occur in many patients suffering from Alzheimer's disease. Little is known about the impact of white matter changes on the course and clinical presentation of Alzheimer's disease. High sensitivity of MRI in the detection of white matter alterations may account for over-diagnosing vascular dementia. The clinical significance of white matter alterations in dementia is still a matter of debate. The article reviews current concepts about the role of white matter alterations in dementia.

Age Factors↗

Three-dimensional true FISP for high-resolution imaging of the whole brain.

While high-resolution T1-weighted sequences, such as three-dimensional magnetization-prepared rapid gradient-echo imaging, are widely available, there is a lack of an equivalent fast high-resolution sequence providing T2 contrast. Using fast high-performance gradient systems we show the feasibility of three-dimensional true fast imaging with steady-state precession (FISP) to fill this gap. We applied a three-dimensional true-FISP protocol with voxel sizes down to 0.5 x 0.5 x 0.5 mm and acquisition times of approximately 8 min on a 1.5-T Sonata (Siemens, Erlangen, Germany) magnetic resonance scanner. The sequence was included into routine brain imaging protocols for patients with cerebrospinal-fluid-related intracranial pathology. Images from 20 patients and 20 healthy volunteers were evaluated by two neuroradiologists with respect to diagnostic image quality and artifacts. All true-FISP scans showed excellent imaging quality free of artifacts in patients and volunteers. They were valuable for the assessment of anatomical and pathologic aspects of the included patients. High-resolution true-FISP imaging is a valuable adjunct for the exploration and neuronavigation of intracranial pathologies especially if cerebrospinal fluid is involved.

Adult↗

[Brain and head injury. Part 1: Clinical classification, imaging modalities, extra-axial injuries, and contusions].

This article describes the imaging tools for efficient diagnostic management of head trauma victims. The basic mechanisms of brain injuries are explained and the imaging features are described. Computed tomography remains the most important method for the initial screening and follow-up investigation. Though magnetic resonance imaging has a higher sensitivity to most traumatic lesions, it does not play an important role in the acute phase of head trauma patients. In the first part of this paper clinical classifications, imaging modalities, extra-axial injuries, and contusions are described. In the second part of this paper intra-axial and secondary injuries are discussed.

Brain↗

[Craniocerebral trauma in childhood].

This article describes typical head injuries in infants and children. In comparison with adults there are distinct differences in the etiology of trauma and in the kind of reaction of the skull and brain. In infants and children there are three different types of trauma: birth trauma, accidental and non-accidental injury. The typical injuries in these three groups are described.

Cerebral Hemorrhage, Traumatic↗

[Stroke in childhood].

About 3% of cerebral infarcts occur in children and young individuals, and pediatric stroke is even less common. Cerebral infarcts in children have different etiologies compared to adults. The common causes are described, as well as sinus venous occlusions. Cerebral veno occlusive disease is an elusive, often underdiagnosed cause of acute neurologic deterioration.

Adolescent↗

[Vascular malformations in newborn infants, infants and children].

Vascular malformations are the cause of nearly all non-traumatic intracranial hemorrhage in children beyond the neonatal stage. Therefore, any child presenting with spontaneous intracranial hemorrhage should be evaluated for child abuse and for vascular malformations. Intracerebral malformations of the cerebral vasculature include vein of Galen malformations, arteriovenous malformation (AVM), cavernomas, dural arteriovenous fistulas, venous anomalies (DVA), and capillary teleangiectasies. Although a few familial vascular malformation have been reported, the majority are sporadic. Clinical symptoms, diagnostic and therapeutic options are discussed.

Adolescent↗

[Supratentorial tumors in childhood].

In Germany about 400 children are diagnosed of having a brain tumour each year. About half of them are located in the supratentorial region. Despite the fact, that brain tumours are the most common solid tumour in childhood, they are very heterogeneous, regarding clinical symptoms, pathology, treatment and prognosis. Imaging studies play an important role for diagnosis and follow-up.

Adolescent↗

Time course of the apparent diffusion coefficient after cerebral infarction.

The purpose of this study was to evaluate quantitative apparent diffusion changes in the center of infarction by measurement of the apparent diffusion coefficient (ADC), and to investigate the influence of ischemia on the contralateral hemisphere. By diffusion echo-planar imaging (EPI) 52 patients showing cerebral infarction were studied within 5 h to >12 months after onset of clinical symptoms. Using three diffusion gradient strengths (b1=30 s/mm(2); b2=300 s/mm(2), b3=1100 s/mm(2)) ADC maps were generated. After onset of ischemia, ADC in the center of infarction was lower than in the contralateral regions of human brain. At first ADC declined for approximately 28 h to a minimum of approximately 150x10(-8) cm(2)/s. Then the ADC reincreased and reached a "pseudonormalization" after approximately 5 days. Chronic infarctions did show much higher ADC values (2000x10(-8) cm(2)/s) than unaffected areas. Neither localization nor size of infarctions showed a significant influence on this time course. In the center of infarction diffusion is isotropic. Even brain regions of the contralateral hemisphere are influenced by cerebral ischemia. In these regions ADC is higher than for physiological conditions. The ADC also declines especially for the first 2-3 days after onset of symptoms, also followed by reincrease. The ADC calculation enables determination of the onset of infarction more exactly than is possible using only diffusion-weighted imaging. Diffusion in the center of infarction is isotropic; hence, orientation of the diffusion gradients has no significant influence on sensitivity of measurements. The calculation of the ADC ratio based on data derived from the center of infarction and the contralateral hemisphere seems to be critical because the ADC in the unaffected contralateral hemisphere also changes.

Brain↗