Search results for "angle"
showing 10 items of 1921 documents
Flip-angle measurement by magnetization inversion: Calibration of magnetization nutation angle in hyperpolarized 3 He magnetic resonance imaging lung…
2010
The aim of this work was to establish a new, fast, and robust method of flip-angle calibration for magnetic resonance imaging of hyperpolarized 3He. The method called flip-angle measurement with magnetization inversion is based on acquiring images from periodically inverted longitudinal magnetization created using the spatial modulation of magnetization technique. By measuring the width of the area where the magnetization was inverted by the spatial modulation of magnetization preparation in phase images, the flip angle can be generated using a simple equation. To validate and establish the limits of the proposed method, flip-angle measurement with magnetization inversion acquisitions were …
Fusingin vivoandex vivoNMR sources of information for brain tumor classification
2011
In this study we classify short echo-time brain magnetic resonance spectroscopic imaging (MRSI) data by applying a model-based canonical correlation analyses algorithm and by using, as prior knowledge, multimodal sources of information coming from high-resolution magic angle spinning (HR-MAS), MRSI and magnetic resonance imaging. The potential and limitations of fusing in vivo and ex vivo nuclear magnetic resonance sources to detect brain tumors is investigated. We present various modalities for multimodal data fusion, study the effect and the impact of using multimodal information for classifying MRSI brain glial tumors data and analyze which parameters influence the classification results…
MRI of inner ear fluids using modified GRASS sequences: a useful tool in the assessment of the normal and pathological labyrinth
1995
MRI is acquiring a progressively more important role in the investigation of petrous bone disease. Nevertheless, despite the extensive use of MRI in the detection of inflammatory or neoplastic involvement of the seventh and eighth cranial nerves, conventional spinecho images cannot be considered the modality of choice in inner ear imaging “Steady-state sequences” are known to be motion sensitive. By setting a very short repetition time, a large flip angle and a long echo time, one can obtain a sequence sufficiently sensitive to the slow movement of endo- and perilymph. We report our experience in MRI of normal and pathological inner ear with modified GRASS sequences.
Proteome alterations in aqueous humour of primary open angle glaucoma patients.
2019
Aim To unravel the primary open angle glaucoma (POAG) related proteomic changes in aqueous humour (AH). Methods Totally 35 patients listed for cataract surgery (controls: n=12, age: 67.4±13.6y) or trabeculectomy for POAG (n=23, age: 72.5±8.3y) were included. AH samples of those patients were obtained during cataract surgery or trabeculectomy. AH samples were subsequently pooled into the experimental groups under equal contribution in terms of protein amount of each individual patient. Protein samples were analyzed by a linear trap quadrupol Orbitrap Mass Spectrometry device with an upstream liquid chromatography system. The obtained raw data were analyzed using the Maxquant proteome softwar…
Malignant paroxysmal positional vertigo
2011
Objective: An insidious percentage of paroxysmal positional vertigo appears to be intractable with canalith repositioning maneuver and also is not self-limiting. This type of positional vertigo is sustained by the action of intracranial tumors that mimics the clinical aspects of benign paroxysmal positional vertigo.Aim of this study is to clarify the features of these forms of positional vertigo, which we indicate as malignant paroxysmal positional vertigo. Methods: We retrospectively reviewed the clinical records of all the patients who presented with vertigo spells and were managed at our tertiary care referral centre over a three years period. Two hundred and eleven patients with diagnos…
Lipid profile of tenon's capsule in glaucoma patients
2009
International audience; Purpose: To provide data on the lipid profile of the Tenon’s capsule in Human glaucomatous eyes and to establish possible relationships with the short term outcome of filtration surgery. Methods: Fragments of Tenon’s capsule were collected during glaucoma surgery in patients suffering from open angle glaucoma (10 trabeculectomies and 17 non penetrating deep sclerectomies). The lipid profile of the human samples was determined by gas chromatography. A successful outcome after glaucoma surgery was defined by an intraocular pressure (IOP) ≤ 15 mmHg at 6 months without any IOP‐lowering agent. Results: We included 27 patients (12 males, 15 females) with a mean age of 65.5…
Current Status of Epibulbar Anti-glaucoma Drainage Devices in Glaucoma Surgery
2012
SUMMARY Background: The term “glaucoma” covers a hetero geneous group of progressive optic neuropathies that are accompanied by characteristic visual-field defects. Primary open-angle glaucoma, the most common type, progresses insidiously and causes blindness if untreated. All current forms of treatment aim at lowering the intraocular pressure (IOP) in patients whose IOP is elevated. The implantation of anti-glaucoma drainage systems is one of the available options for surgical treatment. Methods: This review is based on pertinent literature retrieved by a selective search, including glaucoma treatment guidelines from Germany and abroad. Results: A paradigm shift is currently underway regar…
Latanoprost-induced iris darkening: a morphometric study of human peripheral iridectomies.
2003
Abstract Purpose. This microscopic study was undertaken to compare the melanocytes of peripheral iridectomy specimens from two eyes that had latanoprost-induced iris darkening (LIID) with iridectomies taken from the fellow untreated eyes. Methods. The two patients in this study were the ones who underwent LIID in the latanoprost treated eye from a series of 17 patients requiring bilateral trabeculectomy. The first trabeculectomy procedure provided a control peripheral iridectomy for each patient, whereas the second eye was treated with once daily 50 μg ml−1 latanoprost drops for 6 months. The four peripheral iridectomy specimens from the two LIID patients were subjected to quantitative morp…
In-vitro-Untersuchung von biologischen und technischen Herzklappenprothesen im MRT: Beurteilung möglicher Anziehung und Erhitzung der Implantate
2000
PURPOSE In vitro evaluation of possible deflection and heating of present-day prosthetic heart valves during MR imaging at 1.5 T. METHODS 17 prosthetic heart valves, 12 technical and 5 biological, were investigated using a 1.5 Tesla Siemens Vision system. Deflection was measured at the edge of a 1.5 Tesla superconducting magnet. Each valve was then submerged in a vial of a 1/1 electrolyte solution and temperature was measured before and after imaging with a turbo-spin-echo sequence (TR 5200 ms, TE 138 ms, Flip angle 180 degrees, acquisition time 10.5 minutes, length of echo train 29). MR imaging was performed with phase encoding parallel and perpendicular to the plane of the valves. RESULTS…
Canine fossa puncture in endoscopic sinus surgery: report of two cases
2017
Abstract Introduction Chronic rhinosinusitis with nasal polyposis is a common chronic disease that often affects maxillary sinus. Endoscopic sinus surgery is the most common procedure for treating the majority of maxillary sinus lesions. Objective To demonstrate the role of canine fossa puncture during endoscopic sinus surgery procedure in patients with severe maxillary sinus disease. Methods We present 2 cases where canine fossa puncture has been performed as method to obtain a complete access to the maxillary antrum. Results According our experience, 2 cases on 296 endoscopic sinus surgery (0.6%) where antrostomy and used of angled microdebrider were not sufficient, canine fossa puncture …