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Biomedical subjects

K Verstreken

Publications and source records attributed to K Verstreken.

7 recordsLinked to original sources

PreOp endoscopy simulator: from bronchoscopy to ureteroscopy.

The high cost of virtual reality simulators has posed a major obstacle to the widespread adoption of simulators for medical training. HT Medical broke through this cost barrier by developing the PreOp Flexible Bronchoscopy simulator, a realistic training simulation system that integrates force feedback, multimedia, and 3D graphics on a PC. We are currently extending the PreOp platform so that it can simulate other endoscopic procedures. This paper discusses our efforts to extend the platform to simulate flexible sigmoidoscopy and ureteroscopy.

Bronchoscopy↗

Predictability of a three-dimensional planning system for oral implant surgery.

OBJECTIVES: To compare 2D CT alone with 2D + 3D reconstruction for pre-operative planning of implant placement. METHODS: Spiral CT scans of 33 consecutive patients were used for both reformatted 2D and 3D computer-assisted planning. The number, site and size of implants and the occurrence of anatomical complications during planning and implant placement were statistically compared using the percentage agreement and the Kendall's correlation coefficients (tau). Although planning was performed in 33 patients, implants were only placed in 21 patients. In 11 patients surgery was based on 2D + 3D imaging and in ten patients on 2D planning. RESULTS: Agreement between planning and placement of implants was highly significant for the implant sites selected. For 2D based planning and placement, agreement reached 68% (tau = 0.94). For 2D + 3D based planning and placement, agreement attained 73% (tau = 0.89). For planning and placement of implant size based on 2D images, agreement was 31% and not significant (tau = 0.23). When based on 2D + 3D images, agreement for implant size was 44% (tau = 0.5). Agreement was not significant for anatomical complications: 69% for 2D planning and 71% for 2D + 3D planning (tau = 0.24 for 2D and tau = 0.21 for 2D + 3D). CONCLUSIONS: The 3D planning system is a reliable tool for pre-operative assessment of implant placement. Both 2D and 2D + 3D planning have a good predictability for the number and site of the implants but less so for anatomical complications. However, the 2D + 3D planning provides a better pre-operative assessment of implant size.

Adult↗

An image-guided planning system for endosseous oral implants.

A preoperative planning system for oral implant surgery was developed which takes as input computed tomographies (CT's) of the jaws. Two-dimensional (2-D) reslices of these axial CT slices orthogonal to a curve following the jaw arch are computed and shown together with three-dimensional (3-D) surface rendered models of the bone and computer-aided design (CAD)-like implant models. A technique is developed for scanning and visualizing an eventual existing removable prosthesis together with the bone structures. Evaluation of the planning done with the system shows a difference between 2-D and 3-D planning methods. Validation studies measure the benefits of the 3-D approach by comparing plans made in 2-D mode only with those further adjusted using the full 3-D visualization capabilities of the system. The benefits of a 3-D approach are then evident where a prosthesis is involved in the planning. For the majority of the patients, clinically important adjustments and optimizations to the 2-D plans are made once the 3-D visualization is enabled, effectively resulting in a better plan. The alterations are related to bone quality and quantity (p < 0.05), biomechanics (p < 0.005), and esthetics (p < 0.005), and are so obvious that the 3-D plan stands out clearly (p < 0.005). The improvements often avoid complications such as mandibular nerve damage, sinus perforations, fenestrations, or dehiscences.

Dental Implantation, Endosseous↗

Computer-assisted planning of oral implant surgery. An approach using virtual reality.

A planning system for oral implant surgery is described. This system allows the interactive placement and adjustment of models representing oral implants on CT volume data. These CT data can be shown as two-dimensional (2D) slices, or as a three-dimensional (3D) surface-rendered model. The viewpoint is fully adaptable, and stereoscopy results in an enhanced insight in the interrelation between implants and structures. This approach offers many advantages when compared with the traditional manual planning or with a 2D computer based planning. Clinical trials are being performed.

Computer Simulation↗

[Clinical application of three-dimensional spiral CT in skeletal disorders].

Three-dimensional (3D) computed tomographic reformations are used as an adjunct to standard axial computed tomography (CT) in the evaluation of disorders affecting areas of complex anatomy such as the skull, the spine, the pelvis, hands and feet. 3D-CT can provide a clear impression of lesion extent, pattern, shape and proximity to adjacent structures. This unique spatial information potentially has a significant impact on decisions regarding resectability, surgical approach and repair. The basic requirements for high-quality 3D-reformations are an absence of patient movement and narrow-width transaxial sections. Spiral CT significantly contributes to fulfilling these requirements. In addition, spiral CT scan data can be used to produce the ultimate representation of the third dimension: a life-size palpable medical model. In this review we describe the process of three-dimensional reconstruction and highlight potential problems arising during 3D-imaging processing. Useful clinical applications of spiral CT for 3D-visualization of skeletal pathology are discussed.

Bone Diseases↗

Using WWW and JAVA for image access and interactive viewing in an integrated PACS.

We start from the observations that (1) potential benefits from PACS can only be realized if PACS and HIS are integrated into a 'multimedia medical information system', and (2) that this also requires integration at the level of the user interface. The user interface should allow integrated interaction with information from different subsystems, of which PACS is one. However, in the real world, different information systems are constructed using different technologies. Moreover, radiological image viewing is a highly interactive task that puts a particular burden on the graphical user interface. We describe our experiences in applying technology emerging around the 'World Wide Web' (WWW) for interactive access to an integrated PACS/HIS. We illustrate the use of Web browsers to access new medical services, touch technologies for interactive access to HIS-PACS information, and emphasize the potential of JAVA applets. We argue that JAVA may become an important tool for providing highly interactive user interfaces to larger multimedia information systems. We discuss Web technology in the general context of HIS/PACS integration.

Archives↗

Computer-assisted planning of oral implant surgery: a three-dimensional approach.

A planning system for oral implant surgery based on a true three-dimensional approach is described. This system allows the interactive placement and adjustment of axial-symmetric models representing implants in the jawbone structures visible on computerized tomographic volume data. Simultaneous visualization is possible on two-dimensional reformatted images and on three-dimensional-derived bone surface representations. This approach largely outperforms the manual planning practice based on two-dimensional dental computerized tomographic images printed or on film.

Computer Simulation↗