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Bernd Tomandl

Publications and source records attributed to Bernd Tomandl.

16 recordsLinked to original sources
PubMed2006

Course of platelet activation and platelet-leukocyte interaction in cerebrovascular ischemia.

BACKGROUND AND PURPOSE: Platelet activation plays a crucial role in the pathophysiology of cerebral ischemia. The aim of this study was to investigate the contribution of platelet activation and leukocyte-platelet interactions to the disease. METHODS: One hundred thirty-five patients with transient ischemic attack (TIA) or stroke were enrolled in this single-center study. They underwent cranial computer tomography within 24 hours of clinical onset and after 3 months, and systemic venous blood samples were drawn. Platelet activation (CD62P expression), leukocyte activation (L-selectin expression), and the appearance of platelet-specific antigens on leukocytes as an index of platelet-leukocyte aggregation were measured by flow cytometric techniques in the acute state and at 3-month follow-up. RESULTS: Patients with a completed stroke or TIA had significantly increased circulating platelet-leukocyte aggregates, increased P-selectin expression on platelets, and decreased L-selectin expression in the acute state compared with the control group (healthy volunteers). No differences in regard to the tested activation markers could be detected between patients with stroke or TIA in the acute phase of the disease. However, platelet and leukocyte activations were normalized after 3 months in patients with TIA, whereas leukocyte activation (reduced L-selectin expression) remained in stroke patients. CONCLUSIONS: In patients with TIA and completed stroke, platelet and leukocyte activation is substantially enhanced in the acute phase of the disease. The sustained leukocyte activation observed in stroke but not in TIA patients at 3-month follow up might play a pathophysiological role in the course of the disease.

Aged↗
PubMed2006

Preoperative grading of gliomas by using metabolite quantification with high-spatial-resolution proton MR spectroscopic imaging.

PURPOSE: To evaluate proton magnetic resonance (MR) spectroscopic imaging with high spatial resolution for preoperative grading of suspected World Health Organization grades II and III gliomas. MATERIALS AND METHODS: Institutional ethics committee approval and informed consent were obtained for control subjects but were not required for the retrospective component involving patients. Twenty-six patients (10 women, 16 men; mean age, 37.5 years) suspected of having gliomas and 26 age- and sex-matched control subjects underwent proton MR spectroscopy. Absolute metabolite concentrations for choline-containing compounds (Cho), creatine (Cr), and N-acetylaspartate (NAA)-N-acetylaspartylglutamate (total NAA [tNAA]) were calculated by using a user-independent spectral fit program. Metabolic maps of Cho/tNAA ratios were calculated, segmented, and used for MR spectroszpcopy-guided stereotactic brain biopsy. Two-sided paired Student t tests were used to test for statistical significance. RESULTS: Significantly lower Cho levels (P = .002) and higher tNAA levels (P = .010) were found in grade II tumors (n = 9) compared with grade III tumors (n = 17). The average Cho/tNAA ratio over the voxels in the tumor center showed a distinct difference (P < .001) between grade II and III gliomas at a threshold of 0.8 (with ratios <0.8 for grade II). The maximum Cr concentration in the tumor showed a clear-cut threshold between grade III oligodendrogliomas and oligoastrocytomas (Cr level, <7 mmol/L) and grade III astrocytomas (Cr level, >7 mmol/L; P = .020). Comparison between the histopathologic findings from the MR spectroscopy-guided biopsy samples (76 biopsies from 26 patients) and molar metabolite values in corresponding voxels located at the biopsy sampling points showed a negative linear correlation for tNAA (r = -0.905) and a positive exponential correlation for Cho (r = 0.769) and Cho/tNAA (r = 0.885). CONCLUSION: Proton MR spectroscopic imaging with high spatial resolution allows preoperative grading of gliomas.

Adolescent↗
PubMed2005

Kyphosis reduction and the rate of cement leaks after vertebroplasty of intravertebral clefts.

To assess the results of vertebroplasty in patients with intravertebral clefts compared to patients with normal osteoporotic fractures, we evaluated the pre- and postoperative images and pain scores (VAS) of 114 patients with 192 vertebroplasty procedures treated between March 2002 and February 2005. Intravertebral clefts were identified on conventional radiographs, MR or CT images as gas- or fluid-filled spaces adjacent to an endplate of a fractured vertebra. Forty-four vertebrae showed intravertebral clefts. All clefts were filled with PMMA showing a typical filling pattern. Due to the prone positioning of the patient during vertebroplasty, a significant reduction of the kyphosis angle was achieved in the cleft group. Cement leakage occurred in 18.2% of clefts and 46% of regular osteoporotic fractures. In all patients, good filling of the cleft was achieved no matter where the needle tip was placed in the vertebra. The VAS score was 9.1 preoperatively, 3.6 before discharge and 3.9 6 months postoperatively, showing no significant difference between both groups. Patients with intravertebral clefts show a significant reduction of the kyphosis angle compared to non-cleft patients and have a significantly lower risk of experiencing cement leakage during vertebroplasty. Pain reduction is the same in both groups.

Aged↗
PubMed2005

Taste disorders in acute stroke: a prospective observational study on taste disorders in 102 stroke patients.

BACKGROUND AND PURPOSE: The aim of the study was to assess whether and how frequently patients with acute first-ever stroke exhibit gustatory dysfunction. METHODS: We performed a 1-year prospective observational study. Gustatory function was assessed using the standardized "taste strips" test. In addition, we assessed olfactory function, swallowing, stroke location, comorbidities, and the patients' medication. RESULTS: A total of 102 consecutive patients were enrolled (45 female, 57 male; mean age, 63 years); 31 of them (30%) exhibited gustatory loss and 7 (6%) had lateralized impairment of taste function. Predictors of impaired taste function were male gender (P=0.003), high National Institutes of Health Stroke Scale (NIHSS) score at admission (P=0.009), coexisting swallowing dysfunction (P=0.026), and a stroke of partial anterior circulation subtype (PACS) (P=0.008). In particular, in hypogeusic patients the lesion was most frequently localized in the frontal lobe (P=0.009). Follow-up examinations in 14 patients indicated improvement of taste sensitivity. CONCLUSIONS: Taste disorders after stroke are frequent. A significant association was found for male gender, high NIHSS score, swallowing disorder, and PACS, particularly in the frontal lobe. Generally, taste disorders after stroke seem to have a good prognosis.

Adult↗
PubMed2004

Cortical activity associated with auditory hallucinations.

Auditory hallucinations are one the most enigmatic and hampering symptoms associated with schizophrenia. Non-invasive functional imaging techniques have begun to delineate the underlying neuronal basis. We investigated the spontaneous magnetoencephalographic activity in a 33-year-old male schizophrenic patient and compared the results to those obtained from 13 healthy controls. Despite current neuroleptic medication (clozapine) the patient was still suffering from auditory hallucinations. Using the dipole density method, we were able to demonstrate an increase of fast MEG activity (12.5-30 Hz) in the left auditory cortex associated with hallucinations. This activity was absent in healthy controls. We conclude that an increase in fast MEG activity in the auditory cortex is a neurophysiologic correlate for auditory hallucinations in schizophrenia.

Adult↗
PubMed2004

Three-dimensional visualization of neurovascular relationships in the posterior fossa: technique and clinical application.

OBJECT: The goal of this study was to describe the authors' technique for three-dimensional (3D) visualization of neurovascular relationships in the posterior fossa at the surface of the brainstem. This technique is based on the processing of high-resolution magnetic resonance (MR) imaging data. The principles and technical details involved in the accurate simultaneous visualization of vessels and cranial nerves as tiny structures are presented using explicit and implicit segmentation as well as volume rendering. METHODS: In this approach 3D MR constructive interference in steady state imaging data served as the source for image processing, which was performed using the Linux-based software tools SegMed for segmentation and Qvis for volume rendering. A sequence of filtering operations (including noise reduction and closing) and other software tools such as volume growing are used for a semiautomatic coarse segmentation. The subsequent 3D visualization in which implicit segmentation is used for the differentiation of cranial nerves, vessels, and brainstem is achieved by allocating opacity and color values and adjusting the related transfer functions. This method was applied to the presurgical evaluation in a consecutive series of 55 patients with neurovascular compression syndromes and the results were correlated to surgical findings. The potential for its use, further developments, and remaining problems are discussed. CONCLUSIONS: This method provides an excellent intraoperative real-time virtual view of difficult anatomical relationships.

Brain Stem↗
PubMed2004

Prevention of work-related decompression illness events by detection of a cardiac right-to-left shunt.

A 44-year-old tunnel worker was studied who suffered from several unexplained decompression illness events for almost 15 years. This caisson worker was affected after standard pressure profiles that did not cause symptoms of decompression illness in his colleagues on the same shift. Transesophageal echocardiography revealed an atrial septal defect (grade II) in this otherwise healthy man. Cranial magnetic resonance imaging showed ischemic brain lesions. Among divers, patent foramen ovale, the most common cause of cardiac right-to-left shunts, was shown to increase the risk for decompression illness events by a factor of 4.5 and to double the risk of ischemic brain lesions. Hyperbaric workers with symptoms of unexplained decompression illness, even if they are only slight, should immediately be transferred to a cardiologist so that a cardiac right-to-left shunt will not be overlooked.

Adult↗
PubMed2003

Analysis and 3-dimensional visualization of neurovascular compression syndromes.

RATIONALE AND OBJECTIVES: Neurovascular compression syndromes are currently examined with 2-dimensional representations of tomographic volumes. To overcome this drawback, coarse segmentation followed by direct volume rendering of magnetic resonance (MR) data is introduced supporting a detailed 3-dimensional analysis of the related structures. MATERIALS AND METHODS: This approach is based on MR-CISS (constructive interference in steady state) volumes providing the required high resolution to achieve an improved spatial understanding. In relation to the size of the involved nerves and vessels, an explicit segmentation is extremely difficult. Therefore, a semi-automatic preprocessing sequence was developed consisting of noise reduction, morphologic filtering, and volume growing. To delineate the target structures within the segmented and labeled subvolumes, interactive direct volume rendering was applied that allows delineating the target structures in the area of the cerebrospinal fluid with implicit segmentation based on predefined transfer functions assigning opacity and color values to the intensity values of the image data. For a further improved analysis, registration of the MR-CISS volumes with MR angiography is recommended to support differentiating vessels and nerves on the one side and arteries and veins on the other. RESULTS: The presented method was applied in a consecutive series of 47 cases of different neurovascular compression syndromes, supporting the presurgical analysis of the image data. Additionally, the results were compared with the operative findings. CONCLUSION: Overall, this approach contributes significantly to an optimized 3-dimensional analysis and understanding of neurovascular compression syndromes. Based on the obtained results, it is of high value for the planning of surgery.

Constriction, Pathologic↗
PubMed2003

Multiple brain abscesses caused by Fusobacterium nucleatum treated conservatively.

BACKGROUND: Multiple brain abscesses are serious neurological problems with high mortality and disabling morbidity. The frequency is rising as a result of AIDS and the increasing number of immunocompromised patients. CASE STUDY: A 59-year-old woman developed signs and symptoms of diffuse brain dysfunction including fever and neck stiffness. A brain CT scan demonstrated nine contrast-enhancing ring-shaped lesions. Analysis of the cerebrospinal fluid using PCR-technique revealed DNA of Fusobacterium nucleatum. Conservative treatment with antibiotics was successful. The patient recovered with only mild cognitive deficits. RESULTS: The experience of our patient and the review of the literature indicate that multiple brain abscesses due to Fusobacterium nucleatum are rare. The most probable source is oral infection. CONCLUSION: Multiple brain abscesses may be caused by Fusobacterium nucleatum. Cerebrospinal fluid analysis using PCR technique is helpful with diagnosis. Conservative management can be successful.

Anti-Bacterial Agents↗
PubMed2002

Low-field magnetic resonance imaging for intraoperative use in neurosurgery: a 5-year experience.

The aim of this study was to evaluate the feasibility and point out the indications of intraoperative MR imaging in neurosurgical procedures. The MR imaging was performed using a 0.2-T scanner which was located in a radiofrequency-shielded operating theater. Three major setups for intraoperative imaging were possible: inside the scanner; at the 5-Gauss line; or in an adjacent operating theater. Additionally, in lesions adjacent to eloquent brain areas microscope- and pointer-based neuronavigation with integrated functional data was applied. Three hundred ten patients were investigated in the previous 5 years, among them gliomas ( n=95), pituitary tumors ( n=81), and 39 non-lesional cases in whom resective or disconnective epilepsy surgery was carried out. We did not observe any adverse effects due to intraoperative MR imaging. Image quality was sufficient to evaluate the extent of the tumor resection in the majority of cases. The main indications for intraoperative MR imaging were the evaluation of the extent of a resection in glioma, ventricular tumor, pituitary tumor, and in epilepsy surgery. Intraoperative MR imaging offers the possibility of further tumor removal during the same surgical procedure in case of tumor remnants, increasing the rate of complete tumor removal. Furthermore, the effects of brain shift, which would lead to inaccurate neuronavigation, can be compensated for by an update of the neuronavigation system with intraoperative MR image data.

Adult↗