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Biomedical subjects

B Tomandl

Publications and source records attributed to B Tomandl.

32 records · Page 2Linked to original sources
PubMed2000

Chemical shift imaging spectroscopy and memory function in temporal lobe epilepsy.

PURPOSE: Hippocampal neuron loss and associated memory deficits are characteristic of intractable temporal lobe epilepsy (TLE). Proton chemical shift imaging (CSI) spectroscopy is a sensitive tool for detecting neuronal loss. The aim of this study was to investigate the correlation between memory functions and results provided by CSI spectroscopy of the hippocampal structures. METHODS: Ten patients with cryptogenic TLE participated. The study protocol involved both the acquisition of high-spatial-resolution CSI spectroscopy and neuropsychological evaluation, including memory testing and intracarotid sodium amytal test (IAT). The analysis of the CSI data was based on normative data obtained in 30 healthy volunteers. Memory functions were represented by verbal, visual, and general memory indices. RESULTS: A significant correlation was found between CSI spectroscopy of the hippocampal formation and the verbal memory indices for the dominant hemisphere. In addition, there was a significant correspondence of the qualitative judgment "hippocampal pathology indicated by CSI spectroscopy" and both "material specific memory deficit" and "memory deficit in the IAT." CONCLUSIONS: Our results demonstrate that CSI spectroscopy of the hippocampal structures is strongly related to lateralized memory deficits in patients with TLE. This suggests that CSI spectroscopy may be useful in the prediction of postoperative outcome in respect of seizure control and memory.

Adult↗
PubMed1999

Integration of functional magnetic resonance imaging supported by magnetoencephalography in functional neuronavigation

OBJECTIVE: In this study, the intraoperative visualization of functional data provided by functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) leading to functional neuronavigation is demonstrated in surgery around the motor strip. METHODS: In seven patients with lesions adjacent to the central region, fMRI was performed with a 1.5-Tesla magnetic resonance system, using axial echo-planar imaging with a motor and a sensory task. Somatosensory and motor evoked fields were recorded with a biomagnetometer. fMRI and MEG were matched to an anatomic three-dimensional magnetic resonance image set by a contour fit. Then this three-dimensional image data set was transferred to the navigation microscope and displayed in the eyepieces of the microscope during surgery. Additionally, intraoperative recording of somatosensory evoked potentials was performed for verification of the central sulcus. RESULTS: In all cases, the projection of fMRI and MEG data into the operating viewing field allowed easy identification of the central region, which was confirmed by phase reversal of somatosensory evoked potentials in each case. fMRI and MEG measurements yielded corresponding results in each patient. CONCLUSION: Functional neuronavigation with integration of fMRI and MEG allows the fast identification of eloquent brain areas. The widespread availability of fMRI will result in a broad availability of functional neuronavigation, which will, in turn, contribute to the successful surgery of lesions in eloquent brain areas with lower morbidity.

Journal Article↗
PubMed1997

Three-dimensional MR myelography of the lumbar spine: comparative case study to X-ray myelography.

Conventional myelography was compared with a new type of MR technique using a fat-suppressing 3D fast imaging with steady precession (FISP) sequence for diagnosis of the lumbar root compression syndrome. 80 patients with discogenic disease in the lumbar spine were examined with a 1.0-T whole-body MR system (Siemens Magnetom Impact, Erlangen, Germany). A strongly T2(*)-weighted 3D FISP sequence was applied in the sagittal orientation. To obtain fat suppression, a frequency-selective 1-3-3-1 prepulse was applied prior to the imaging sequence. The acquired 3D data set was evaluated using a maximum intensity projection (MIP) program. The measurement time was 7 min, 47 s. Magnetic resonance myelography has significant advantages over conventional myelography, particularly in cases of extreme spinal canal stenosis. Compared with the conventional method, this new MR technique shows comparable sensitivity in the visualization of the spinal nerve roots in the lumbar spine.

Case-Control Studies↗
PubMed1997

[Value of CT-angiography in the diagnosis of cerebral artery aneurysms].

PURPOSE: In a clinical study 35 patients with intracranial aneurysms were examined using CT-angiography, MR-angiography (MRA) and digital subtraction angiography (DSA). The aim of the study was to establish the ability of noninvasive techniques to detect intracranial aneurysms. MATERIAL AND METHODS: The CT examinations were performed using a spiral CT scanner and the MR investigations with a 1.5 T whole body MR-system. We used for MR-angiography Time of Flight (TOF) and Phase Contrast (PC) techniques. For postprocessing reconstructions modalities Maximum Intensity Projection (MIP), Surface and Volume Rendering Technique (VRT) techniques were used. The results were evaluated by the intraoperative findings. RESULTS: Aneurysms up to 5 mm could be detected best using CTA and DSA. Giant aneurysms could be evaluated best using CTA. Volume rendering technique was the most useful postprocessing procedure. MRA using Time of Flight was superior compared with MRA using PC technique. CONCLUSION: CTA is the best method to detect and to evaluate giant intracranial aneurysms. Nevertheless the reconstruction mode has a decisive influence on the results.

Adult↗
PubMed1997

Color Doppler imaging versus phlebography in the diagnosis of deep leg and pelvic vein thrombosis.

The objective of this prospective study was to evaluate the accuracy of color Doppler imaging in comparison to phlebography in diagnosing phlebothrombosis. Five hundred and twenty-six phlebographies (reference method) were compared with 526 color Doppler sonographic examinations. Thrombosis diagnosed with color Doppler imaging showed a sensitivity of 98.0% (400 of 408). In 91.6% (482 of 526) of all examinations the extent of the thrombosis diagnosed with phlebography could also be seen with color Doppler imaging. When the clinical situation is unclear, color Doppler imaging should precede phlebography. Only when findings with ultrasonography are questionable should phlebography definitely be considered.

Adolescent↗
PubMed1995

[An unusual case of endometriosis].

Endometriosis can be found in 10 to 20% of all menstruating women. Most often the lesions are localized in the pelvis, but in rare cases they can be found in almost every region of the body. The diagnostic clue is the typical history of premenstrual pain. Imaging can demonstrate the site and size of extra-pelvic lesions and an image-guided diagnostic puncture for histological diagnosis can be done.

Adult↗
PubMed1992

[Roentgen findings in T-drainage--results of 311 patients].

Postoperative T Tube cholangiographies of 311 patients from 1980 to February 1992 were evaluated by studying the patient histories and x-ray examinations. Most frequent questions concerned residual stones and papillary occlusion. Most frequent pathological findings were dilatation of the choledochus and of the bile ducts, residual stones and paravasations. Fistulas, abscesses and signs of cholangitis rarely occurred. Dilatation of the choledochus alone did not lead to further treatment. Papillary occlusion was treated by leaving the T drain in situ, patients with occlusion and residual stones were treated by papillotomy, litholysis or lithotripsy. Only 5 patients with necrotizing pancreatitis and abscess had to be reoperated. T tube cholangiography, which at the beginning of the study was a routine postoperative control with minor complications, will surely be applied less frequently in the future due to advances in endoscopy.

Aged↗
PubMed1992

[Results of computerized tomography after Whipple operation of chronic pancreatitis].

53 patients were controlled with CT after Whipple resection. The median age of the patients was 49 years, the median time after surgery nine years. Diagnostic criteria were the identification of the residual pancreas, signs of pancreatic atrophy and radiological signs of chronic pancreatitis. CT was performed with slice thickness of 4 mm and steps of 4 mm. The residual pancreas was visible in all 53 cases. Pancreatic atrophy was found in 26 cases, in four of these the residual pancreas was only 2 mm in size. Signs of chronic pancreatitis were found in 16 cases. By comparing preoperative and postoperative CT-scans, seven progresses of pancreatitis were detected. Signs of acute pancreatitis were not found in the 53 patients. Fatty liver degeneration was found in 7.5%. We found that CT is the most reliable technique to visualize the pancreas after Whipple resection. CT should be performed in all patients with clinical symptoms of an acute pancreatitis. CT should also be performed in patients with residual pancreas pseudocysts. There is no indication for CT in the routine examination of asymptomatic patients after Whipple resection.

Adult↗
PubMed1991

[Comparison of CT and plain tomography in hilar and lung processes].

A group of 100 patients including 46 patients with suspected bronchogenic carcinoma and 54 patients with suspected lung metastases was evaluated by conventional plain tomography. Patients with preoperatively suspected T4- or N3-categories were excluded. The diagnosis was confirmed in all cases by surgery and histology. In addition, patients with lung metastases were controlled by follow-up chest x-rays (median follow-up time 1.5 years). The diagnosis of plain tomography was true positive in 70% and false in 30%. CT was true positive in 57% and incorrect in 43%. Tumors or metastases were detected with both methods when more than 5 mm in diameter, lesions smaller than 5 mm were overlooked with CT and tomography. Plain tomography an CT did not detect lymph nodes metastases smaller than 1.0 cm.

Carcinoma, Bronchogenic↗
PubMedDate not supplied

Peripheral nerve stimulation by time-varying magnetic fields.

PURPOSE: A study was performed to assess the stimulation threshold for healthy adults using sinusoidally oscillating gradients. METHOD: One hundred thirteen healthy adults were examined in the study. ECG and physiological parameters were measured. All measurements were performed of both the head and the abdomen. The subjects were measured in the supine position with the region of interest positioned in the center of the gradient coils. The measurement was performed for three orthogonal, four oblique, and double oblique orientations. RESULTS: No volunteer reported painful, severe stimulation. The mean thresholds for peripheral stimulation in head and body measurement were similar: 85.5% of stimulation during examination of the head and 87.6% during measurements of the abdomen were reported when the y-gradient was used. CONCLUSION: The greatest frequency of reported stimulations occurs when the y-gradient is used. This was confirmed by the results and supports the hypothesis that orthogonal to the y-axis the body has its largest conductive loop, resulting in the strongest peripheral stimulation.

Adult↗