Objective. To evaluate a newly developed laserbased imaging technique for the study of soft tissue changes and acute inflammatory processes of the proximal interphalangeal (PIP) joints in patients with rheumatoid arthritis (RA).Methods. A novel imaging device was developed which allows the transillumination of PIP joints using laser light in the near-infrared wavelength range. In a first clinical followup study, a total of 72 PIP joints of 22 patients with RA and 64 PIP joints of 8 healthy controls were examined both clinically and with the new laser device. At baseline and at followup after a mean of 6 weeks, clinical signs of synovitis, the joint circumference, and the degree of pain were assessed for each PIP joint in order to determine the clinical degree of inflammation. Different features were extracted from the laser images and evaluated by a neural network.Results. At baseline, 72 PIP joints in the RA patients showed clinical signs of inflammation. At followup, 45 PIP joints showed clinical improvement, 13 showed steady active inflammation, and 14 showed deterioration compared with the first visit. None of the 64 PIP joints in the healthy individuals showed any signs of synovitis. The inflammatory status of 60 of the 72 RA joints examined was classified correctly by laser examination and joint circumference determination, giving a sensitivity of 80%, a specificity of 89%, and an accuracy of 83% in detecting inflammatory changes in affected joints. Laser data and joint circumference determination of healthy joints at followup resulted in an accuracy of 85% in reproducing the image.Conclusion. The new laser-based imaging technique allows the transillumination of PIP joints and gives information about the inflammatory status of the joint after processing through a neural network. Our data indicate that laser imaging may provide additional information in the early diagnosis of an inflammatory joint process and may prove particularly useful in assessing acute joint inflammation at followup.
Die endoskopische Infrarot-Diaphanoskopie ist ein Verfahren mit dem Ziel, eine Orientierungsverbesserung in der Nasenhaupthöhle bei endoskopisch kontrollierten, endonasalen Eingriffen im Bereich der Nasennebenhöhle zu erreichen. Die Durchleuchtung soll es ermöglichen, die natürlichen Zugänge von den Nasennebenhöhlen (NNH) zur Nasenhaupthöhle unter endoskopischer Sicht besser zu lokalisieren. Die vorliegende Arbeit spezifiziert die notwendigen Voraussetzungen anhand von In-vitro-Untersuchungen am Tiermodell (Schaf) und am humanen Halbkopfpräparat. Fragen, für welche NNH eine Durchleuchtung prinzipiell möglich ist, ob die Durchleuchtung ein Auffinden der natürlichen Übergänge von einzelnen Nasennebenhöhlen zur Nasenhaupthöhle ermöglicht und welche gerätetechnischen Anforderungen erfüllt werden müssen, werden beantwortet. · ·
Key words: Infrared Diaphanoscopy -endonasal surgery -nasal cavities -in vitro investigationEndoscopic infrared diaphanoscopy is a method of improving orientation in the nasal cavity during endoscopy-controlled endonasal surgery. The transillumination is expected to f acilitate the localisation of the natural passageways between the paranasal sinuses and the nasal cavity during endoscopic procedures. The present study specifies the necessary conditions on the basis of in vitro examinations using an animal model (sheep) and an anatomical preparation of half of the human head. The questions äs to what paranasal sinus is at all accessible to diaphanoscopy, whether the method actually enables the connecting pathways between an individual sinus and the nasal cavity to be identified, and what technical demands need to be met, are considered and answered.
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