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In this study a computer aided navigation technique for accurate positioning of oral implants was assessed. An optical tracking system with specially designed tools for monitoring the position of surgical instruments relative to the patient was used to register 5 partially or completely edentulous jaw models. Besides the accuracy of the tracking system, the(More)
3D/2D registration, the automatic assignment of a global rigid-body transformation matching the coordinate systems of patient and preoperative volume scan using projection images, is an important topic in image-guided therapy and radiation oncology. A crucial part of most 3D/2D registration algorithms is the fast computation of digitally rendered(More)
OBJECTIVE The aim of this study was to establish a correlation between bone mineral density measured preoperatively with dental computed tomography (CT), and insertion torque of screw-shaped dental implants. MATERIAL AND METHODS In eight human mandibles obtained postmortem, bone mineral density (BMD) was measured with dental quantitative CT (DQCT) and(More)
Registration of single slices from FluoroCT, CineMR, or interventional magnetic resonance imaging to three dimensional (3D) volumes is a special aspect of the two-dimensional (2D)/3D registration problem. Rather than digitally rendered radiographs (DRR), single 2D slice images obtained during interventional procedures are compared to oblique reformatted(More)
Ziel dieses Beitrags ist die Vorstellung der Untersuchungsmöglichkeiten des Ober- und Unterkiefers mittels Magnetresonanztomographie (Dental-MRT) und ihre Anwendung bei der Diagnose zahnmedizinischer Erkrankungen. Sieben gesunde Probanden, 5 Patienten mit Pulpitis, 9 Patienten mit dentogenen Zysten, 5 Patienten nach Zahntransplantationen und 12 Patienten(More)
PURPOSE To correlate torque forces during insertion of screw-type dental implants with bone mineral density (BMD) values determined preoperatively. MATERIALS AND METHODS Dental quantitative computed tomography (CT) was performed with simultaneous imaging of five postmortem mandibles and a calibration standard containing defined concentrations of calcium(More)
Computer-aided surgery (CAS), the intraoperative application of biomedical visualization techniques, appears to be one of the most promising fields of application for augmented reality (AR), the display of additional computer-generated graphics over a real-world scene. Typically a device such as a head-mounted display (HMD) is used for AR. However,(More)
PURPOSE To compare the performance of 64-slice with 16-slice CT scanners for the in vitro evaluation of coronary artery stents. METHODS AND MATERIALS Twelve different coronary artery stents were placed in the drillings of a combined heart and chest phantom, which was scanned with a 16- and 64-slice CT scanner. Coronal reformations were evaluated for(More)
To evaluate coronary stents in vitro using 128-slice-dual-source computed tomography (CT). Twelve different coronary stents placed in a non-moving cardiac/chest phantom were examined by 128-slice dual-source CT using three CT protocols [high-pitch spiral (HPS), sequential (SEQ) and conventional spiral (SPIR)]. Artificial in-stent lumen narrowing (ALN),(More)
OBJECTIVE Many studies have suggested that Hounsfield measurements on unenhanced CT can reliably differentiate adrenal adenomas from nonadenomas using a scanner-independent threshold level. The purpose of this study was to determine whether establishment of a scanner-independent threshold for differentiation of adenomas from nonadenomas is technically(More)