10 results on '"Wetzel, S"'
Search Results
2. Diffusion-weighted MRI in cortical ischaemia
- Author
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L�vblad, K. O., primary, Wetzel, S. G., additional, Somon, T., additional, Wilhelm, K., additional, Mehdizade, A., additional, Kelekis, A, additional, El-Koussy, M., additional, El-Tatawy, S., additional, Bishof, M., additional, Schroth, G., additional, Perrig, S., additional, Lazeyras, F., additional, Sztajzel, R., additional, Terrier, F., additional, R�fenacht, D., additional, and Delavelle, J., additional
- Published
- 2004
- Full Text
- View/download PDF
3. Radiation dose in vertebroplasty
- Author
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Kelekis, A. D., primary, Yilmaz, H., additional, Abdo, G., additional, Martin, J. B., additional, Viera, J. M., additional, R�fenacht, D. A., additional, Mehdizade, A., additional, Lovblad, K. O., additional, Wilhelm, K. E., additional, Somon, T., additional, and Wetzel, S. G., additional
- Published
- 2004
- Full Text
- View/download PDF
4. ADC mapping of the aging frontal lobes in mild cognitive impairment.
- Author
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Lövblad, K.O., Delavelle, J., Wetzel, S., Kelekis, A.D., Assal, F., Palmesino, M., Gold, G., Yilmaz, H., Ruiz, D. San Millan, Lazeyras, F., Mehdizade, A., and Rüfenacht, D.A.
- Subjects
DIAGNOSTIC imaging ,MEDICAL imaging systems ,AGING ,VASCULAR diseases ,NEURORADIOLOGY ,DEMENTIA - Abstract
Normal aging, leukoaraiosis (LA) and vascular disease particularly involve the human frontal lobes. We decided to investigate a population of elderly patients referred for neuroimaging because of progressive minor cognitive deficits but no dementia. They underwent conventional Magnetic resonance imaging (MRI) using axial T1 and T2-weighted imaging as well as coronal FLAIR sequences in addition to the axial diffusion-weighted MRI. MRI allowed us to differentiate patients with leukoaraïosis (LA+) from those without it (LA-) and mapping of the apparent diffusion coefficient (ADC) to investigate local tissular water motion.We observed an increase in the ADC in all investigated patients with increasing age (r=0.326, p=0.002). This increase was observed in both patients groups (LA+ and LA-) . In addition, the LA+ group had significant higher ADC values than the LA- group after controlling for age (p<0.0001). [ABSTRACT FROM AUTHOR]
- Published
- 2004
5. Dural venous sinus stenting as a stand-alone treatment for spontaneous skull base CSF leak secondary to venous pseudotumor cerebri syndrome.
- Author
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San Millán D, Hallak B, Wanke I, Wetzel S, Van Dommelen K, Rüfenacht D, and Gailloud P
- Subjects
- Aged, Cerebrospinal Fluid Rhinorrhea diagnostic imaging, Female, Humans, Magnetic Resonance Imaging, Pseudotumor Cerebri diagnostic imaging, Tomography, X-Ray Computed, Cerebrospinal Fluid Rhinorrhea etiology, Cerebrospinal Fluid Rhinorrhea surgery, Pseudotumor Cerebri complications, Stents, Transverse Sinuses surgery
- Abstract
Most spontaneous CSF leaks (SCSFL) are associated with an underlying pseudotumor cerebri syndrome (PTCS). Treatment generally includes surgical leak repair and PTCS correction, as untreated PTCS carries a risk of recurrence. We describe a 72-year-old woman with rhinorrhea, aural fullness, and posterior nasal drip. CT and MRI showed signs of CSF hypovolemia and PTCS, as well as bilateral transverse sinus stenoses. CT and MRI cisternography documented CSF leaks through the right cribriform plate and the posterior aspect of the petrous bone. Opening CSF pressure was 6 cm H
2 O. Dural venous sinus stenting (DVSS) was performed after failed conservative treatment. Rhinorrhea resolved 3 days after stenting, aural fullness 1 month later. After 6 months, signs of CSF hypovolemia had disappeared on MRI and the stents were patent. After 9 months, the patient had a transient, spontaneously resolving episode of rhinorrhea. She has been symptom-free for the remaining 39 months of follow-up.- Published
- 2019
- Full Text
- View/download PDF
6. Evaluation of a novel, patient-mounted system for CT-guided needle navigation-an ex vivo study.
- Author
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Mokry A, Willmitzer F, Hostettler R, Richter H, Kircher P, Kneissl S, and Wetzel S
- Subjects
- Algorithms, Computer Simulation, Humans, Phantoms, Imaging, Software, Needles, Punctures, Radiography, Interventional instrumentation, Tomography, X-Ray Computed
- Abstract
Purpose: To describe the features of a novel patient-mounted system for CT-guided needle navigation, the Puncture Cube System (PCS), and to evaluate the accuracy and efficiency of the PCS by (a) applying numerical simulations and (b) by conducting punctures using the system in comparison to punctures using the free-hand method (FHM)., Methods: The PCS consists of a self-adhesive cube that is attached to the patient, with multiple through-holes in the upper and lower template plate and dedicated software that, using a computer vision algorithm, recognizes the cube in a planning scan. The target in the image dataset is connected by a line, here "virtual needle," which passes through the cube. For any chosen path of the virtual needle, the entry points for the needle into the cube are displayed by the software for the upper and lower template on-the-fly. The possible exactness of the system was investigated by using numerical simulations. Next, 72 punctures were performed by 6 interventionists using a phantom to compare for accuracy, time requirement, and number of CT scans for punctures with the system to the FHM ex vivo (phantom study)., Results: The theoretical precision to arrive at targets increased with the distance of the target but remained low. The mean error for targets up to 20 cm below the lower plate was computed to be well below 0.5 mm, and the worst-case error stayed below 1.3 mm. Compared to a conventional free-hand procedure, the use of the navigation system resulted in a statistically significantly improved accuracy (3.4 mm ± 2.3 mm versus FHM 4.9 mm ± 3.2 mm) and overall lower intervention time (168 s ± 28.5 s versus FHM 200 s ± 44.8 s). Furthermore, the number of CT scans was reduced to 2.3 versus FHM 2.8)., Conclusion: The PCS is a promising technique to improve accuracy and reduce intervention time in CT-guided needle navigations compared to the FHM.
- Published
- 2019
- Full Text
- View/download PDF
7. Diffusion-weighted imaging in acute demyelinating myelopathy.
- Author
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Zecca C, Cereda C, Wetzel S, Tschuor S, Staedler C, Santini F, Nadarajah N, Bassetti CL, and Gobbi C
- Subjects
- Acute Disease, Adult, Female, Humans, Male, Middle Aged, Reproducibility of Results, Sensitivity and Specificity, Demyelinating Diseases pathology, Diffusion Magnetic Resonance Imaging methods, Spinal Cord pathology, Spinal Cord Diseases pathology
- Abstract
Introduction: Diffusion-weighted imaging (DWI) has become a reference MRI technique for the evaluation of neurological disorders. Few publications have investigated the application of DWI for inflammatory demyelinating lesions. The purpose of the study was to describe diffusion-weighted imaging characteristics of acute, spinal demyelinating lesions., Methods: Six consecutive patients (two males, four females; aged 28-64 years) with acute spinal cord demyelinating lesions were studied in a prospective case series design from June 2009 to October 2010. We performed magnetic resonance imaging studies from 2 to 14 days from symptom onset on the patients with relapsing remitting multiple sclerosis (n = 3) or clinically isolated syndrome (n = 3). Main outcome measures were diffusion-weighted imaging and apparent diffusion coefficient pattern (ADC) of acute spinal cord demyelinating lesions., Results: All spinal lesions showed a restricted diffusion pattern (DWI+/ADC-) with a 24% median ADC signal decrease. A good correlation between clinical presentation and lesion site was observed., Conclusion: Acute demyelinating spinal cord lesions show a uniform restricted diffusion pattern. Clinicians and neuro-radiologists should be aware that this pattern is not necessarily confirmatory for an ischaemic aetiology.
- Published
- 2012
- Full Text
- View/download PDF
8. Double-lumen balloon microcatheter-assisted occlusion of cerebral vessels with coils: a technical note.
- Author
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Handa A, Abdo G, Yilmaz H, Wetzel SG, Lovblad KO, Bijlenga P, De Tribolet N, and Rufenacht DA
- Subjects
- Adult, Carotid Artery Diseases therapy, Female, Humans, Male, Vertebral Artery, Balloon Occlusion, Catheterization, Embolization, Therapeutic, Intracranial Aneurysm therapy
- Abstract
The purpose of this study was to describe a balloon-assisted double-lumen microcatheter technique to perform a controlled and tight coil packing of a vascular segment for vessel occlusion. This technique can be performed immediately after a test occlusion with the balloon kept in place and was, as illustrated in six cases, in our experience safe, straight forward to use and fast.
- Published
- 2004
- Full Text
- View/download PDF
9. Diffusion-weighted MRI in cortical ischaemia.
- Author
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Lövblad KO, Wetzel SG, Somon T, Wilhelm K, Mehdizade A, Kelekis A, El-Koussy M, El-Tatawy S, Bishof M, Schroth G, Perrig S, Lazeyras F, Sztajzel R, Terrier F, Rüfenacht D, and Delavelle J
- Subjects
- Adolescent, Adult, Aged, Brain pathology, Brain Ischemia mortality, Child, Child, Preschool, Coma diagnosis, Female, Humans, Infant, Infant, Newborn, Male, Middle Aged, Brain Ischemia diagnosis, Cerebral Cortex blood supply, Diffusion Magnetic Resonance Imaging
- Abstract
We carried out MRI on 16 male and three female comatose patients, aged 2 days to 79 years, with suspected cortical ischaemia referred from our intensive care units. Using a head coil, and following standard imaging, including coronal fluid-attenuated inversion-recovery images, we performed diffusion-weighted imaging (DWI) using a whole-brain multislice single-shot echo-planar sequence with b 0 and 1000 s/mm2: 5-mm slices covering the whole brain, TR 7000 TE 106 ms, 128 x 128 pixels, field of view 250 mm, one excitation. Maps of apparent diffusion coefficients (ADC) were generated automatically. DWI showed cortical, basal ganglia and watershed-area high signal in all cases, associated with a decrease in ADC to 60- 80% of normal. DWI showed lesions not seen (40%) or underestimated (40%) on conventional T2-weighted imaging. Within 24 h of the onset of symptoms, DWI showed changes not readily detectable on T2-weighted images. The cortical high signal on DWI and the ADC changes, suggesting severe ischaemia rather than oedema, was found in areas known to be affected by cortical laminar necrosis. Extension to the brain stem and white matter was associated with a higher likelihood of death.
- Published
- 2004
- Full Text
- View/download PDF
10. Radiation dose in vertebroplasty.
- Author
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Mehdizade A, Lovblad KO, Wilhelm KE, Somon T, Wetzel SG, Kelekis AD, Yilmaz H, Abdo G, Martin JB, Viera JM, and Rüfenacht DA
- Subjects
- Aged, Female, Hand radiation effects, Health Personnel, Humans, Injections, Male, Pain etiology, Pain Management, Palliative Care, Radiation Dosage, Spinal Neoplasms complications, Spinal Neoplasms secondary, Bone Cements therapeutic use, Fluoroscopy, Radiography, Interventional, Spine drug effects
- Abstract
We wished to measure the absorbed radiation dose during fluoroscopically controlled vertebroplasty and to assess the possibility of deterministic radiation effects to the operator. The dose was measured in 11 consecutive procedures using thermoluminescent ring dosimeters on the hand of the operator and electronic dosimeters inside and outside of the operator's lead apron. We found doses of 0.022-3.256 mGy outside and 0.01-0.47 mGy inside the lead apron. Doses on the hand were higher, 0.5-8.5 mGy. This preliminary study indicates greater exposure to the operator's hands than expected from traditional apron measurements.
- Published
- 2004
- Full Text
- View/download PDF
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