Biomedical subjects

Ekkehard Euler

Publications and source records attributed to Ekkehard Euler.

4 recordsLinked to original sources

PubMed2004

3D imaging with an isocentric mobile C-arm comparison of image quality with spiral CT.

The purpose of this study was to evaluate the image quality of the new 3D imaging system (ISO-C-3D) for osteosyntheses of tibial condylar fractures in comparison with spiral CT (CT). Sixteen human cadaveric knees were examined with a C-arm 3D imaging system and spiral computed tomography. Various screws and plates of steel and titanium were used for osteosynthesis in these specimens. Image quality and clinical value of multiplanar (MP) reformatting of both methods were analyzed. In addition, five patients with tibial condylar fractures were examined for diagnosis and intra-operative control. The image quality of the C-arm 3D imaging system in the cadaveric study was rated as significantly worse than that of spiral CT with and without prostheses. After implantation of prostheses an increased incidence of artifacts was observed, but the diagnostic accuracy was not affected. Titanium implants caused the smallest number of artifacts. The image quality of ISO-C is inferior to CT, and metal artifacts were more prominent, but the clinical value was equal. ISO-C-3D can be useful in planning operative reconstructions and can verify the reconstruction of articular surfaces and the position of implants with diagnostic image quality.

Artifacts↗

PubMed2004

C-arm-based mobile computed tomography: a comparison with established imaging on the basis of simulated treatments of talus neck fractures in a cadaveric study.

OBJECTIVE: To analyse the image quality and diagnostic effectiveness of a new C-arm-based 3D imaging method (C-arm-CT) for intraoperative evaluation of screw osteosyntheses adjacent to a peripheral joint. MATERIALS AND METHODS: Insertion of screws into four cadaveric specimens simulated the surgical treatment of talus neck fractures. Ten orthopedic surgeons and 10 radiologists evaluated X-ray, C-arm fluoroscopy, C-arm-CT and CT images. RESULTS: The best image quality was obtained with X-rays (p < 0.001), followed by C-arm fluoroscopy (2D) and CT, with the C-arm-CT (3D) being rated lowest (p < 0.001). The most correct diagnoses were obtained with CT and C-arm-CT (with no statistical difference between them), while C-arm-fluoroscopy was inferior (p < 0.001) and X-rays were the worst (p < 0.05). CONCLUSIONS: Even if the image quality of C-arm-CT is definitely inferior to that of CT, screw misplacements can be reliably detected using C-arm-CT. As compared to the current standard procedures (intraoperative fluoroscopy and postoperative radiography), C-arm-CT performed better. C-arm-CT is ideally suited to the intraoperative diagnosis of high-contrast inquiries like bone fragments and OS material, especially at the extremities. Coupling of the new 3D imaging to existing navigation systems is possible. C-arm-CT will support the further development and implementation of open and minimally invasive surgical procedures.

Bone Screws↗

PubMed2003

C-arm-based three-dimensional navigation: a preliminary feasibility study.

OBJECTIVE: With the new Siremobil Iso-C3D C-arm, three-dimensional (3D) datasets can be acquired intraoperatively in near-real time. Preliminary studies investigated the advantages of this system for depiction in joint and spinal surgery. Three-dimensional navigation seems feasible using the DICOM dataset of the Siremobil Iso-C3D in navigation devices. An experimental study was designed to investigate the feasibility and accuracy of this new technique. MATERIALS AND METHODS: After implantation of fiducial markers (titanium mini-screws, Leibinger), a Siremobil Iso-C3D C-arm with standard imaging options was used to acquire pre-interventional 3D datasets of the specimens. These isotropic voxel data were transferred via DICOM to a medivision navigation system using the spine module. After registration of the fiducials, a total of 20 pedicle screws were implanted (in 4 artificial-bone vertebral bodies and 6 cadaver vertebrae in situ) with the use of the navigation system in real-time mode. Post-interventionally, Iso-C3D and CT scans were obtained to control for implant position in the cadaver study. RESULTS: Fiducial marker implantation and registration require a special protocol to ensure correct identification and patient orientation in the DICOM dataset. The obtained accuracy was within 2 mm. Post-interventional imaging of the cadaveric vertebrae showed 10 of 12 screws to be correctly placed, with the other two in marginal intraosseous positions. CONCLUSIONS: Three-dimensional navigation with the Siremobil Iso-C3D data set is feasible, the accuracy being comparable to that of CT-based navigation and adequate for clinical interventions. Fiducial marker-based registration allows navigation of different bones in the same dataset without additional 3D scanning. This method is very useful as an additional tool in registration-free Iso-C3D-based navigation, since the navigation system allows the use of only one dynamic reference base (DRB).

Bone Screws↗

PubMed2002

Three-dimensional CT with a modified C-arm image intensifier: feasibility.

A portable C arm was modified for cone-beam computed tomography (CT). This three-dimensional (3D) CT imaging system facilitated the acquisition of fluoroscopic images during a 190 degrees rotation and computed a 3D data cube (matrix, 256 x 256 x 256; scanning time, 100 seconds) with multiplanar image reformation. The high-contrast resolution, 0.9 line pairs per millimeter, was comparable; the low-contrast resolution, minimal; and the radiation dose, 60%-80% lower, as compared with these parameters at spiral CT. The normal anatomy of small joints could be depicted, and the osteosynthesis screws in the talus were correctly identified.

Bone Screws↗