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Bei der Schultersteife handelt es sich um ein häufiges Krankheitsbild in der Orthopädie bzw. Schulterchirurgie, das sowohl bei Ärztinnen und Ärzten (Allgemeinmedizinerinnen und mediziner, Fachärztinnen und -ärzte) als auch bei sonstigem medizinischem Fachpersonal, z.B. der Physiotherapie oder Pflege, nur einen geringen Bekanntheitsgrad besitzt. Zielorientierung dieser Leitlinie war es, eine fundierte Hilfestellung und Richtlinie in Bezug auf das Krankheitsbild für Ärztinnen, Ärzte und medizinisches Fachpersonal zu schaffen, den aktuellen evidenz-basierten Wissensstand zu vermitteln und eine bessere Patientinnen- und Patientenversorgung zu erzielen, inkl. der intensiven Aufklärung der Betroffenen durch die behandelnden Berufsgruppen und – wenn von den Betroffenen gewünscht – einer gemeinsamen Entscheidungsfindung bezüglich der Behandlung.
Mathematical analysis of the 1D model and reconstruction schemes for magnetic particle imaging
(2018)
Magnetic particle imaging (MPI) is a promising new in vivo medical imaging modality in which distributions of super-paramagnetic nanoparticles are tracked based on their response in an applied magnetic field. In this paper we provide a mathematical analysis of the modeled MPI operator in the univariate situation. We provide a Hilbert space setup, in which the MPI operator is decomposed into simple building blocks and in which these building blocks are analyzed with respect to their mathematical properties. In turn, we obtain an analysis of the MPI forward operator and, in particular, of its ill-posedness properties. We further get that the singular values of the MPI core operator decrease exponentially. We complement our analytic results by some numerical studies which, in particular, suggest a rapid decay of the singular values of the MPI operator.
OBJECTIVES
Due to severe limitations of dental pulp sensitivity tests, the direct recording of pulsed blood flow, using photoplethysmography (PPG), has been proposed. In vivo evaluation is methodologically difficult and in vitro models have hitherto been adversely influenced by shortcomings in emulating the in vivo situation. Consequently, the aim of this study was to test an improved data acquisition system and to use this configuration for recording pulsed blood in a new model.
MATERIALS AND METHODS
We introduced a PPG signal detection system by recording signals under different blood flow conditions at two wavelengths (625 and 940 nm). Pulsed blood flow signals were measured using an in vitro model, containing a molar with a glass pulp and a resin socket, which closely resembled in vivo conditions with regard to volumetric blood flow, pulp anatomy, and surrounding tissue.
RESULTS
The detection system showed improved signal strength without stronger blanketing of noise. On the tooth surface, it was possible to detect signals emanating from pulsed blood flow from the glass pulp and from surrounding tissue at 625 nm. At 940 nm, pulp derived signals were recorded, without interference signals from surrounding tissue.
CONCLUSION
The PPG-based method has the potential to detect pulsed blood flow in small volumes in the pulp and (at 625 nm) also in adjacent tissues.
CLINICAL RELEVANCE
The results show the need for clear differentiation of the spatial origins of blood flow signals of any vitality test method to be applied to teeth.