0000000000281897

AUTHOR

H.-u. Kauczor

showing 3 related works from this author

MRI using hyperpolarized noble gases.

1998

The aim of this study was to review the physical basis of MRI using hyperpolarized noble gases as well as the present status of preclinical and clinical applications. Non-radioactive noble gases with a nuclear spin 1/2 (He-3, Xe-129) can be hyperpolarized by optical pumping. Polarization is transferred from circularly polarized laser light to the noble-gas atoms via alkali-metal vapors (spin exchange) or metastable atoms (metastability exchange). Hyperpolarization results in a non-equilibrium polarization five orders of magnitude higher than the Boltzmann equilibrium compensating for the several 1000 times lower density of noble gases as compared with liquid state hydrogen concentrations in…

In vivo magnetic resonance spectroscopyAdultLung Diseasesmedicine.medical_specialtyQuantitative Biology::Tissues and OrgansPhysics::Medical PhysicsGuinea Pigschemistry.chemical_elementHeliumNoble GasesOptical pumpingMiceXenonNuclear magnetic resonanceIsotopesMetastabilitymedicineIsotopes of xenonImage Processing Computer-AssistedAnimalsHumansRadiology Nuclear Medicine and imagingHyperpolarization (physics)LungHeliumBrain Diseasesmedicine.diagnostic_testbusiness.industryBrainMagnetic resonance imagingGeneral MedicineImage EnhancementMagnetic Resonance ImagingchemistryXenon IsotopesFemaleRadiologybusinessNuclear medicineEuropean radiology
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Hybrid segmentation and exploration of the human lungs

2004

Segmentation of the tracheo-bronchial tree of the lungs is notoriously difficult. This is due to the fact that the small size of some of the anatomical structures is subject to partial volume effects. Furthermore, the limited intensity contrast between the participating materials (air, blood, and tissue) increases the segmentation of difficulties. In this paper, we propose a hybrid segmentation method which is based on a pipeline of three segmentation stages to extract the lower airways down to the seventh generation of the bronchi. User interaction is limited to the specification of a seed point inside the easily detectable trachea at the upper end of the lower airways. Similarly, the comp…

medicine.medical_specialtyLungComputer scienceAnatomical structuresPartial volumeImage segmentationrespiratory systemrespiratory tract diseasesTree (data structure)medicine.anatomical_structuremedicineSegmentationRadiologyRespiratory systemAirwayBiomedical engineeringIEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
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Fallzahlplanung in referenzkontrollierten Diagnosestudien

2002

Purpose: A tutorial illustration of a flexible approach to determine the sample size in reference-controlled diagnostic trials. Materials and Methods: Assuming the usual setting of a new diagnostic method to be compared with a reference method, the emphasis is on the sensitivity of the new method in comparison with the reference method, using a binary outcome (positive versus negative) for both methods. Based on the confidence interval of the sensitivity, a simple but flexible procedure for determining the sample size is described, which incorporates clinically interpretable information. The procedure is illustrated by the fictious planning of a trial to assess the diagnostic value of MRI v…

business.industryComputer scienceDiagnostic TrialMachine learningcomputer.software_genreOutcome (probability)Confidence intervalClinical trialSample size determinationRange (statistics)A priori and a posterioriRadiology Nuclear Medicine and imagingSensitivity (control systems)Artificial intelligencebusinesscomputerRöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren
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