Computer aided surgery : official journal of the International Society for Computer Aided Surgery
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Comput. Aided Surg. · Jan 2005
Measurements of acetabular cup position and pelvic spatial orientation after total hip arthroplasty using computed tomography/radiography matching.
This study presents a clinical validation of postoperative measurements of acetabular cup alignment following total hip arthroplasty (THA). The methodology was based on concurrent anatomic three-dimensional (3D) measurements of both the acetabular cup alignment and pelvic orientation, using an original CT/X-ray matching algorithm named Xalign. The subjects were 19 patients who had undergone bilateral THA using CT-based surgical navigation. ⋯ The mean cup abduction error was 0.85 degrees +/- 1.3 degrees (+/- standard deviation) and the mean version error was 0.01 degrees +/- 1.99 degrees. Conventionally measured cup abduction ranged from 44 degrees to 62 degrees and correlated significantly (p = 0.001, r = -0.5) with pelvic flexion angle, proving the linear negative correlation between pelvic flexion and the error in conventional radiographic cup measurements. The Xalign method offered reasonable accuracy for cup orientation, and allowed cup and pelvic 3D anatomic measurements at different times.
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Comput. Aided Surg. · Jan 2004
Comparative StudyThree-dimensional comparison of interventional MR radiofrequency ablation images with tissue response.
Solid tumors are being treated using radiofrequency (RF) ablation under interventional magnetic resonance imaging (MRI) guidance. We are investigating the ability of MRI to monitor ablation treatments by comparing MR images of thermal lesions to histologically assayed tissue damage. ⋯ This is good evidence that MR thermal lesion images can be used during RF ablation treatments to accurately localize the zone of necrosis at the lesion margin.
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Comput. Aided Surg. · Jan 2004
Comparative StudyC-arm-based mobile computed tomography: a comparison with established imaging on the basis of simulated treatments of talus neck fractures in a cadaveric study.
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. ⋯ 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.
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Comput. Aided Surg. · Jan 2004
Patient-specific bronchoscope simulation with pq-space-based 2D/3D registration.
The use of patient-specific models for surgical simulation requires photorealistic rendering of 3D structure and surface properties. For bronchoscope simulation, this requires augmenting virtual bronchoscope views generated from 3D tomographic data with patient-specific bronchoscope videos. To facilitate matching of video images to the geometry extracted from 3D tomographic data, this paper presents a new pq-space-based 2D/3D registration method for camera pose estimation in bronchoscope tracking. ⋯ The proposed method does not involve explicit feature extraction and is relatively immune to illumination changes. The temporal variation of the pq distribution also permits the identification of localized deformation, which offers an effective way of excluding such areas from the registration process.
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Comput. Aided Surg. · Jan 2003
Accuracy of computer assisted percutaneous placement of iliosacral screws: a cadaveric study.
To determine the accuracy of computer-assisted fluoronavigation for percutaneous iliosacral screw placement. ⋯ The results of this study support the safety and accuracy of computer-assisted fluoronavigation for iliosacral screw placement. The advantages include decreased fluoroscopic time, real-time simultaneous visualization of all three views (inlet, outlet, and lateral), and increased accuracy of placement. Clinical study is warranted.